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Homothety

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245: 4943: 158: 1568: 1950: 2828: 31: 1958: 4669: 4053: 4413: 5268: 4792: 1942: 4188: 5680: 5159: 3857: 3764: 5039: 3896: 1323: 5422: 1514: 505: 5333: 412: 5539: 5085: 4360: 4664:{\displaystyle S_{3}:\mathbf {s} _{3}={\frac {(1-k_{1})k_{2}\mathbf {s} _{1}+(1-k_{2})\mathbf {s} _{2}}{1-k_{1}k_{2}}}=\mathbf {s} _{1}+{\frac {1-k_{2}}{1-k_{1}k_{2}}}(\mathbf {s} _{2}-\mathbf {s} _{1})} 2354: 1223: 5167: 2660: 4684: 576: 1389: 4285: 3488: 1162: 1429: 4937: 3353: 3055: 1817: 4059: 3629: 2982: 3589: 1856: 2929: 2468: 2258: 2189: 4406: 3303: 2041: 3888: 3537: 3095: 4239: 3436: 3669: 3253: 3213: 2869: 1936: 1896: 5575: 5092: 4864: 3770: 3390: 2751: 3677: 5563: 5460: 1547: 1248: 961: 438: 351: 2777: 1744: 793: 767: 185: 148: 117: 58: 4966: 4891: 4827: 3009: 2696: 2068: 1771: 1714: 1687: 1660: 1633: 924: 4048:{\displaystyle (\sigma _{2}\sigma _{1})(\mathbf {x} )=\mathbf {s} _{2}+k_{2}{\big (}\mathbf {s} _{1}+k_{1}(\mathbf {x} -\mathbf {s} _{1})-\mathbf {s} _{2}{\big )}} 670: 215: 2120: 893: 706: 634: 535: 85: 5480: 5353: 3163: 3143: 3123: 2817: 2797: 2534: 2514: 2491: 2394: 2374: 2091: 1606: 1343: 1182: 1129: 981: 859: 730: 604: 326: 302: 239: 5715: 1253: 5366: 1434: 834:, a homothetic transformation is a similarity transformation (i.e., fixes a given elliptic involution) that leaves the line at infinity pointwise 450: 5280: 5861: 5488: 5046: 359: 4290: 5721: 5690: 5263:{\displaystyle =\mathbf {s} +{\frac {\mathbf {v} }{1-k}}+k\left(\mathbf {x} -(\mathbf {s} +{\frac {\mathbf {v} }{1-k}})\right)} 2263: 1187: 1048:), meaning "position". It describes the relationship between two figures of the same shape and orientation. For example, two 4787:{\displaystyle \sigma _{2}\sigma _{1}:\ \mathbf {x} \to \mathbf {s} _{3}+k_{1}k_{2}(\mathbf {x} -\mathbf {s} _{3})\quad } 2543: 269: 1351: 4244: 3447: 1134: 1055:
Homotheties are used to scale the contents of computer screens; for example, smartphones, notebooks, and laptops.
1394: 543: 4183:{\displaystyle \qquad \qquad \ =(1-k_{1})k_{2}\mathbf {s} _{1}+(1-k_{2})\mathbf {s} _{2}+k_{1}k_{2}\mathbf {x} } 4896: 3312: 3014: 1776: 3594: 2934: 5566: 3557: 835: 3440: 1975: 1822: 796: 2874: 2399: 5686: 2194: 2125: 1553: 1100: 812: 740: 4368: 3265: 5741: 1994: 3865: 3493: 3060: 5718:
on the number of strictly smaller homothetic copies of a convex body that may be needed to cover it
5675:{\displaystyle {\begin{pmatrix}k&0&(1-k)u\\0&k&(1-k)v\\0&0&1\end{pmatrix}}} 5154:{\displaystyle \tau \sigma :\mathbf {x} \to \mathbf {s} +\mathbf {v} +k(\mathbf {x} -\mathbf {s} )} 3852:{\displaystyle \sigma _{2}:\mathbf {x} \to \mathbf {s} _{2}+k_{2}(\mathbf {x} -\mathbf {s} _{2})\ } 3166: 831: 820: 800: 5841: 4201: 3759:{\displaystyle \sigma _{1}:\mathbf {x} \to \mathbf {s} _{1}+k_{1}(\mathbf {x} -\mathbf {s} _{1}),} 3398: 5749: 5702: 3634: 3218: 3178: 2834: 1901: 1861: 736: 4832: 3358: 2701: 5708: 5034:{\displaystyle \sigma :\mathbf {x} \to \mathbf {s} +k(\mathbf {x} -\mathbf {s} ),\;k\neq 1,\;} 1572: 1009: 5548: 5427: 1526: 929: 417: 5799: 3540: 2756: 1719: 772: 746: 218: 164: 127: 96: 37: 4869: 4805: 2987: 2669: 2046: 1749: 1692: 1665: 1638: 1611: 902: 1049: 646: 583: 191: 5711:, the center of a homothetic transformation taking one of a pair of shapes into the other 2099: 868: 683: 613: 514: 64: 1228: 331: 5815: 5465: 5338: 3148: 3128: 3108: 2802: 2782: 2519: 2499: 2476: 2379: 2359: 2076: 1591: 1328: 1318:{\displaystyle \mathbf {x} =k(\mathbf {p} +t\mathbf {v} )=k\mathbf {p} +tk\mathbf {v} } 1167: 1114: 1025: 966: 844: 715: 589: 311: 287: 224: 5855: 5823: 5830:, University Series in Undergraduate Mathematics, Princeton, NJ: D. Van Nostrand Co. 1941: 244: 5845: 4942: 273: 157: 1949: 1567: 5417:{\displaystyle \sigma :\mathbf {x} \to \mathbf {s} +k(\mathbf {x} -\mathbf {s} )} 2827: 253: 30: 1971: 1970:
Before computers became ubiquitous, scalings of drawings were done by using a
1509:{\displaystyle |k\mathbf {p} -k\mathbf {q} |=|k||\mathbf {p} -\mathbf {q} |} 17: 1957: 1561: 500:{\displaystyle \mathbf {x} '=\mathbf {s} +k(\mathbf {x} -\mathbf {s} )} 5328:{\displaystyle \mathbf {s} '=\mathbf {s} +{\frac {\mathbf {v} }{1-k}}} 5795:
H.S.M. Coxeter, "Introduction to geometry" , Wiley (1961), p. 94
1557: 1003:
if the scale factor exceeds 1. The above-mentioned fixed point
2070:
are prolonged at the other end as shown in the diagram. Choose the
4941: 2826: 1956: 1948: 1940: 1566: 243: 156: 29: 1111:
In order to make calculations easy it is assumed that the center
4951:
The composition of a homothety and a translation is a homothety.
5534:{\displaystyle \mathbf {x} \to k\mathbf {x} +(1-k)\mathbf {s} } 5080:{\displaystyle \tau :\mathbf {x} \to \mathbf {x} +\mathbf {v} } 1564:
is a similar one. i.e. the ratio of the two axes is unchanged.
407:{\displaystyle {\overrightarrow {SX'}}=k{\overrightarrow {SX}}} 4355:{\displaystyle \ (1-k_{2})(\mathbf {s} _{2}-\mathbf {s} _{1})} 5462:
can be written as the composition of a homothety with center
1043: 1033: 1746:
can be constructed graphically using the intercept theorem:
1052:
looking in the same direction can be considered homothetic.
799:, all homotheties of an affine (or Euclidean) space form a 5693:
because it is composed of translation and uniform scale.
5810:
Meserve, Bruce E. (1955), "Homothetic transformations",
2349:{\displaystyle |SQ_{0}|={\tfrac {k}{k-1}}|P_{0}Q_{0}|.} 1218:{\displaystyle \mathbf {x} =\mathbf {p} +t\mathbf {v} } 5584: 2294: 5578: 5551: 5491: 5468: 5430: 5369: 5341: 5283: 5170: 5095: 5049: 4969: 4899: 4872: 4835: 4808: 4687: 4416: 4371: 4293: 4247: 4204: 4062: 3899: 3868: 3773: 3680: 3637: 3597: 3560: 3496: 3450: 3401: 3361: 3315: 3268: 3221: 3181: 3151: 3131: 3111: 3063: 3017: 2990: 2937: 2877: 2837: 2805: 2785: 2759: 2704: 2672: 2546: 2522: 2502: 2479: 2402: 2382: 2362: 2266: 2197: 2128: 2102: 2079: 2049: 1997: 1904: 1864: 1825: 1779: 1752: 1722: 1695: 1668: 1641: 1614: 1594: 1549:
the calculation is analogous but a little extensive.
1529: 1437: 1397: 1354: 1331: 1256: 1231: 1190: 1170: 1137: 1117: 969: 932: 905: 871: 847: 775: 749: 718: 686: 649: 616: 592: 546: 517: 453: 420: 362: 334: 314: 290: 227: 194: 167: 130: 99: 67: 40: 1520:(quotient) of two line segments remains unchanged . 2655:{\displaystyle |SQ_{0}|/|SP_{0}|=|Q_{0}Q|/|PP_{0}|} 5674: 5557: 5533: 5474: 5454: 5416: 5347: 5327: 5262: 5153: 5079: 5033: 4931: 4885: 4858: 4821: 4786: 4663: 4400: 4354: 4279: 4233: 4182: 4047: 3882: 3851: 3758: 3663: 3623: 3583: 3531: 3482: 3430: 3384: 3347: 3297: 3247: 3207: 3157: 3137: 3117: 3089: 3049: 3003: 2976: 2923: 2863: 2811: 2791: 2771: 2745: 2690: 2654: 2528: 2508: 2485: 2462: 2388: 2368: 2348: 2252: 2183: 2114: 2085: 2062: 2035: 1930: 1890: 1850: 1811: 1765: 1738: 1708: 1681: 1654: 1627: 1600: 1541: 1508: 1423: 1383: 1337: 1317: 1242: 1217: 1176: 1156: 1123: 975: 955: 918: 887: 853: 795:) the direction of all vectors. Together with the 787: 761: 724: 700: 664: 628: 598: 570: 529: 499: 432: 406: 345: 320: 296: 233: 209: 179: 142: 111: 79: 52: 1028:, is derived from two Greek elements: the prefix 2831:The composition of two homotheties with centers 1063:The following properties hold in any dimension. 3862:one gets by calculation for the image of point 1384:{\displaystyle P:\mathbf {p} ,\;Q:\mathbf {q} } 815:with the property that the image of every line 4280:{\displaystyle {\overrightarrow {S_{1}S_{2}}}} 3483:{\displaystyle {\overrightarrow {S_{1}S_{2}}}} 1516:the distance between their images. Hence, the 586:and shows the meaning of special choices for 4040: 3967: 2396:can be prescribed. In this case the ratio is 1157:{\displaystyle \mathbf {x} \to k\mathbf {x} } 8: 3102:The composition of two homotheties with the 841:In Euclidean geometry, a homothety of ratio 2698:are collinear (lie on a line) and equation 1424:{\displaystyle |\mathbf {p} -\mathbf {q} |} 571:{\displaystyle \mathbf {x} '=k\mathbf {x} } 5030: 5017: 2473:Attach the mobile rods rotatable at point 2096:On the prolonged rods mark the two points 1369: 1071:A homothety has the following properties: 5579: 5577: 5550: 5526: 5503: 5492: 5490: 5467: 5429: 5406: 5398: 5384: 5376: 5368: 5340: 5307: 5305: 5297: 5285: 5282: 5234: 5232: 5224: 5213: 5184: 5182: 5174: 5169: 5143: 5135: 5121: 5113: 5105: 5094: 5072: 5064: 5056: 5048: 5006: 4998: 4984: 4976: 4968: 4917: 4907: 4900: 4898: 4877: 4871: 4850: 4840: 4834: 4813: 4807: 4774: 4769: 4760: 4751: 4741: 4728: 4723: 4714: 4702: 4692: 4686: 4652: 4647: 4637: 4632: 4619: 4609: 4591: 4578: 4569: 4564: 4551: 4541: 4523: 4518: 4508: 4486: 4481: 4474: 4461: 4445: 4436: 4431: 4421: 4415: 4386: 4376: 4370: 4343: 4338: 4328: 4323: 4310: 4292: 4265: 4255: 4248: 4246: 4219: 4209: 4203: 4175: 4169: 4159: 4146: 4141: 4131: 4109: 4104: 4097: 4084: 4061: 4039: 4038: 4032: 4027: 4014: 4009: 4000: 3991: 3978: 3973: 3966: 3965: 3959: 3946: 3941: 3929: 3917: 3907: 3898: 3875: 3867: 3837: 3832: 3823: 3814: 3801: 3796: 3787: 3778: 3772: 3744: 3739: 3730: 3721: 3708: 3703: 3694: 3685: 3679: 3655: 3642: 3636: 3615: 3602: 3596: 3575: 3565: 3559: 3514: 3501: 3495: 3468: 3458: 3451: 3449: 3416: 3406: 3400: 3376: 3366: 3360: 3333: 3323: 3316: 3314: 3283: 3273: 3267: 3239: 3226: 3220: 3199: 3186: 3180: 3150: 3130: 3110: 3079: 3062: 3035: 3025: 3018: 3016: 2995: 2989: 2968: 2955: 2942: 2936: 2913: 2901: 2882: 2876: 2855: 2842: 2836: 2804: 2784: 2758: 2738: 2727: 2716: 2705: 2703: 2671: 2647: 2641: 2629: 2624: 2619: 2610: 2601: 2593: 2587: 2575: 2570: 2565: 2559: 2547: 2545: 2521: 2501: 2478: 2455: 2449: 2437: 2432: 2427: 2421: 2409: 2401: 2381: 2361: 2338: 2332: 2322: 2313: 2293: 2285: 2279: 2267: 2265: 2245: 2239: 2227: 2216: 2210: 2198: 2196: 2176: 2170: 2158: 2147: 2141: 2129: 2127: 2101: 2078: 2054: 2048: 2015: 2002: 1996: 1922: 1909: 1903: 1882: 1869: 1863: 1836: 1826: 1824: 1797: 1787: 1780: 1778: 1757: 1751: 1730: 1721: 1700: 1694: 1673: 1667: 1646: 1640: 1619: 1613: 1593: 1528: 1501: 1496: 1488: 1483: 1478: 1470: 1462: 1457: 1446: 1438: 1436: 1416: 1411: 1403: 1398: 1396: 1376: 1361: 1353: 1330: 1310: 1296: 1282: 1271: 1257: 1255: 1230: 1210: 1199: 1191: 1189: 1169: 1149: 1138: 1136: 1116: 1024:The term, coined by French mathematician 999:. Such a transformation can be called an 968: 947: 942: 933: 931: 910: 904: 880: 872: 870: 846: 774: 748: 743:that fix a point and either preserve (if 717: 690: 685: 648: 615: 591: 563: 548: 545: 516: 489: 481: 467: 455: 452: 419: 389: 363: 361: 333: 313: 289: 226: 193: 166: 129: 98: 66: 39: 27:Generalized scaling operation in geometry 4932:{\displaystyle {\overline {S_{1}S_{2}}}} 3348:{\displaystyle {\overline {S_{1}S_{2}}}} 3172:The composition of two homotheties with 3050:{\displaystyle {\overline {S_{1}S_{2}}}} 1982:Construction and geometrical background: 1812:{\displaystyle {\overline {P_{1}P_{2}}}} 1552:Consequences: A triangle is mapped on a 5761: 3624:{\displaystyle \sigma _{1},\sigma _{2}} 2977:{\displaystyle P_{i}\to Q_{i}\to R_{i}} 1079:is mapped onto a parallel line. Hence: 1067:Mapping lines, line segments and angles 5780: 3584:{\displaystyle \sigma _{2}\sigma _{1}} 1858:. The image of a point collinear with 1662:is given (see diagram) then the image 2984:is a homothety again with its center 7: 5768: 4678:(is not moved) and the composition 1851:{\displaystyle {\overline {SP_{2}}}} 5828:A Modern Introduction to Geometries 2924:{\displaystyle k_{1}=2,k_{2}=0{.}3} 2463:{\displaystyle k=|SQ_{0}|/|SP_{0}|} 4960:The composition of the homothety 2253:{\displaystyle |QQ_{0}|=k|HQ_{0}|} 2184:{\displaystyle |SQ_{0}|=k|SP_{0}|} 2043:such that the two rods meeting at 1987:Take 4 rods and assemble a mobile 25: 5750:monotonically increasing function 5705:a similar notion in vector spaces 5277:which is a homothety with center 3125:is again a homothety with center 1773:is the common point th two lines 5812:Fundamental Concepts of Geometry 5527: 5504: 5493: 5407: 5399: 5385: 5377: 5308: 5298: 5286: 5235: 5225: 5214: 5185: 5175: 5144: 5136: 5122: 5114: 5106: 5073: 5065: 5057: 5007: 4999: 4985: 4977: 4770: 4761: 4724: 4715: 4648: 4633: 4565: 4519: 4482: 4432: 4401:{\displaystyle k_{1}k_{2}\neq 1} 4339: 4324: 4176: 4142: 4105: 4028: 4010: 4001: 3974: 3942: 3930: 3876: 3833: 3824: 3797: 3788: 3740: 3731: 3704: 3695: 3298:{\displaystyle k_{1}k_{2}\neq 1} 2753:holds. That shows: the mapping 2662:(see diagram) one gets from the 1497: 1489: 1458: 1447: 1412: 1404: 1377: 1362: 1311: 1297: 1283: 1272: 1258: 1211: 1200: 1192: 1150: 1139: 564: 549: 490: 482: 468: 456: 5722:Homothetic function (economics) 4783: 4064: 4063: 2036:{\displaystyle P_{0},Q_{0},H,P} 1588:If for a homothety with center 1556:one. The homothetic image of a 1184:with parametric representation 5641: 5629: 5609: 5597: 5523: 5511: 5497: 5449: 5437: 5411: 5395: 5381: 5252: 5221: 5148: 5132: 5110: 5061: 5011: 4995: 4981: 4946:Composition with a translation 4780: 4757: 4719: 4658: 4628: 4514: 4495: 4467: 4448: 4349: 4319: 4316: 4297: 4137: 4118: 4090: 4071: 4020: 3997: 3934: 3926: 3923: 3900: 3883:{\displaystyle X:\mathbf {x} } 3843: 3820: 3792: 3750: 3727: 3699: 3532:{\displaystyle k_{1}=k_{2}=-1} 3145:. The homotheties with center 3090:{\displaystyle k\cdot l=0{.}6} 2961: 2948: 2763: 2739: 2728: 2717: 2706: 2648: 2630: 2620: 2602: 2594: 2576: 2566: 2548: 2456: 2438: 2428: 2410: 2339: 2314: 2286: 2268: 2246: 2228: 2217: 2199: 2177: 2159: 2148: 2130: 1502: 1484: 1479: 1471: 1463: 1439: 1417: 1399: 1325:, which is a line parallel to 1287: 1268: 1143: 943: 934: 881: 873: 494: 478: 1: 1560:is a circle. The image of an 1225:is mapped onto the point set 1109:Derivation of the properties: 4924: 4234:{\displaystyle k_{1}k_{2}=1} 3431:{\displaystyle k_{1}k_{2}=1} 3340: 3042: 2516:and mark at each time point 1843: 1804: 4241:a translation in direction 4194:Hence, the composition is 3664:{\displaystyle S_{1},S_{2}} 3248:{\displaystyle k_{1},k_{2}} 3208:{\displaystyle S_{1},S_{2}} 2864:{\displaystyle S_{1},S_{2}} 2779:is a homothety with center 2496:Vary the location of point 2376:the location of the center 1931:{\displaystyle P_{2},Q_{2}} 1891:{\displaystyle P_{1},Q_{1}} 1584:using the intercept theorem 1348:The distance of two points 5878: 5844:, interactive applet from 4859:{\displaystyle k_{1}k_{2}} 3385:{\displaystyle k_{1}k_{2}} 2746:{\displaystyle |SQ|=k|SP|} 1088:ratio of two line segments 1044: 1038:), meaning "similar", and 1034: 811:. These are precisely the 5862:Transformation (function) 5804:Lessons in Plane Geometry 5724:, a function of the form 5359:In homogenous coordinates 1716:, which lies not on line 3309:with its center on line 1898:can be determined using 444:Using position vectors: 34:Homothety: Example with 5567:homogeneous coordinates 5565:can be represented in 5558:{\displaystyle \sigma } 5455:{\displaystyle S=(u,v)} 3591:of the two homotheties 1961:Pantograph 3d rendering 1579:Graphical constructions 1542:{\displaystyle S\neq O} 1094:Both properties show: 956:{\displaystyle |k|^{3}} 433:{\displaystyle k\neq 0} 5676: 5559: 5535: 5476: 5456: 5418: 5349: 5329: 5264: 5155: 5081: 5035: 4947: 4933: 4887: 4860: 4823: 4788: 4665: 4402: 4356: 4281: 4235: 4184: 4049: 3884: 3853: 3760: 3665: 3625: 3585: 3533: 3484: 3432: 3386: 3349: 3299: 3249: 3209: 3159: 3139: 3119: 3098: 3091: 3051: 3005: 2978: 2925: 2865: 2813: 2793: 2773: 2772:{\displaystyle P\to Q} 2747: 2692: 2656: 2530: 2510: 2487: 2464: 2390: 2370: 2350: 2260:. This is the case if 2254: 2185: 2116: 2087: 2064: 2037: 1974:, a tool similar to a 1962: 1954: 1953:Geometrical background 1946: 1932: 1892: 1852: 1813: 1767: 1740: 1739:{\displaystyle SP_{1}} 1710: 1683: 1656: 1629: 1602: 1575: 1543: 1510: 1425: 1385: 1339: 1319: 1244: 1219: 1178: 1158: 1125: 985:ratio of magnification 977: 957: 920: 889: 855: 813:affine transformations 809:homothety-translations 789: 788:{\displaystyle k<0} 763: 762:{\displaystyle k>0} 726: 702: 666: 630: 600: 572: 531: 501: 434: 408: 347: 322: 298: 276:determined by a point 249: 248:Homothety of a pyramid 241: 235: 211: 181: 180:{\displaystyle k<0} 154: 144: 143:{\displaystyle k<1} 113: 112:{\displaystyle k>1} 81: 54: 53:{\displaystyle k>0} 5687:linear transformation 5677: 5560: 5536: 5477: 5457: 5419: 5350: 5330: 5265: 5156: 5082: 5036: 4945: 4934: 4888: 4886:{\displaystyle S_{3}} 4861: 4824: 4822:{\displaystyle S_{3}} 4789: 4666: 4403: 4357: 4282: 4236: 4185: 4050: 3885: 3854: 3761: 3666: 3626: 3586: 3534: 3485: 3433: 3387: 3350: 3300: 3250: 3210: 3160: 3140: 3120: 3092: 3052: 3006: 3004:{\displaystyle S_{3}} 2979: 2926: 2866: 2830: 2814: 2794: 2774: 2748: 2693: 2691:{\displaystyle S,P,Q} 2657: 2531: 2511: 2488: 2465: 2391: 2371: 2351: 2255: 2186: 2117: 2088: 2065: 2063:{\displaystyle Q_{0}} 2038: 1960: 1952: 1944: 1933: 1893: 1853: 1814: 1768: 1766:{\displaystyle Q_{2}} 1741: 1711: 1709:{\displaystyle P_{2}} 1684: 1682:{\displaystyle Q_{2}} 1657: 1655:{\displaystyle P_{1}} 1630: 1628:{\displaystyle Q_{1}} 1603: 1570: 1544: 1511: 1426: 1386: 1340: 1320: 1245: 1220: 1179: 1159: 1126: 978: 958: 921: 919:{\displaystyle k^{2}} 890: 856: 790: 764: 727: 703: 667: 631: 601: 573: 532: 502: 435: 409: 348: 323: 299: 284:and a nonzero number 247: 236: 212: 182: 160: 145: 114: 82: 55: 33: 5742:homogeneous function 5576: 5549: 5489: 5466: 5428: 5367: 5339: 5281: 5168: 5093: 5047: 4967: 4897: 4870: 4833: 4806: 4685: 4414: 4369: 4291: 4245: 4202: 4060: 3897: 3866: 3771: 3678: 3635: 3595: 3558: 3554:For the composition 3494: 3448: 3399: 3359: 3313: 3266: 3219: 3179: 3149: 3129: 3109: 3061: 3015: 2988: 2935: 2875: 2835: 2803: 2783: 2757: 2702: 2670: 2544: 2520: 2500: 2477: 2400: 2380: 2360: 2264: 2195: 2126: 2100: 2077: 2047: 1995: 1902: 1862: 1823: 1777: 1750: 1720: 1693: 1666: 1639: 1612: 1592: 1527: 1435: 1395: 1352: 1329: 1254: 1229: 1188: 1168: 1135: 1115: 1019:center of similitude 1015:center of similarity 967: 930: 903: 869: 845: 773: 747: 739:homotheties are the 716: 684: 665:{\displaystyle k=-1} 647: 614: 590: 544: 515: 451: 418: 360: 332: 312: 308:, which sends point 288: 266:homogeneous dilation 225: 210:{\displaystyle k=-1} 192: 165: 128: 97: 91:(no point is moved), 65: 38: 5716:Hadwiger conjecture 5482:and a translation: 5041:and the translation 2115:{\displaystyle S,Q} 888:{\displaystyle |k|} 832:projective geometry 712:mapping defined by 701:{\displaystyle 1/k} 629:{\displaystyle k=1} 530:{\displaystyle S=O} 414:for a fixed number 80:{\displaystyle k=1} 5818:, pp. 166–169 5703:Scaling (geometry) 5672: 5666: 5555: 5531: 5472: 5452: 5414: 5345: 5325: 5260: 5151: 5077: 5031: 4948: 4929: 4883: 4856: 4819: 4784: 4661: 4398: 4352: 4277: 4231: 4180: 4045: 3880: 3849: 3756: 3661: 3621: 3581: 3529: 3480: 3428: 3382: 3345: 3295: 3245: 3205: 3155: 3135: 3115: 3099: 3087: 3047: 3001: 2974: 2921: 2861: 2809: 2789: 2769: 2743: 2688: 2652: 2526: 2506: 2483: 2460: 2386: 2366: 2346: 2311: 2250: 2181: 2112: 2083: 2060: 2033: 1966:using a pantograph 1963: 1955: 1947: 1928: 1888: 1848: 1809: 1763: 1736: 1706: 1689:of a second point 1679: 1652: 1625: 1598: 1576: 1539: 1506: 1421: 1381: 1335: 1315: 1243:{\displaystyle g'} 1240: 1215: 1174: 1154: 1121: 973: 953: 916: 885: 865:between points by 851: 785: 759: 737:Euclidean geometry 722: 698: 662: 626: 596: 568: 527: 497: 430: 404: 346:{\displaystyle X'} 343: 318: 294: 250: 242: 231: 207: 177: 155: 140: 109: 77: 50: 5709:Homothetic center 5685:A pure homothety 5475:{\displaystyle O} 5348:{\displaystyle k} 5323: 5250: 5200: 4927: 4713: 4626: 4558: 4296: 4275: 4067: 3848: 3541:point reflections 3490:. Especially, if 3478: 3343: 3174:different centers 3158:{\displaystyle S} 3138:{\displaystyle S} 3118:{\displaystyle S} 3045: 2812:{\displaystyle k} 2792:{\displaystyle S} 2664:intercept theorem 2529:{\displaystyle Q} 2509:{\displaystyle P} 2486:{\displaystyle S} 2389:{\displaystyle S} 2369:{\displaystyle k} 2310: 2086:{\displaystyle k} 1846: 1807: 1601:{\displaystyle S} 1573:intercept theorem 1338:{\displaystyle g} 1177:{\displaystyle g} 1124:{\displaystyle S} 1098:A homothety is a 1083:remain unchanged. 1010:homothetic center 976:{\displaystyle k} 854:{\displaystyle k} 769:) or reverse (if 725:{\displaystyle k} 599:{\displaystyle k} 402: 381: 321:{\displaystyle X} 297:{\displaystyle k} 234:{\displaystyle S} 16:(Redirected from 5869: 5831: 5819: 5806: 5784: 5778: 5772: 5766: 5681: 5679: 5678: 5673: 5671: 5670: 5564: 5562: 5561: 5556: 5540: 5538: 5537: 5532: 5530: 5507: 5496: 5481: 5479: 5478: 5473: 5461: 5459: 5458: 5453: 5423: 5421: 5420: 5415: 5410: 5402: 5388: 5380: 5354: 5352: 5351: 5346: 5334: 5332: 5331: 5326: 5324: 5322: 5311: 5306: 5301: 5293: 5289: 5269: 5267: 5266: 5261: 5259: 5255: 5251: 5249: 5238: 5233: 5228: 5217: 5201: 5199: 5188: 5183: 5178: 5160: 5158: 5157: 5152: 5147: 5139: 5125: 5117: 5109: 5086: 5084: 5083: 5078: 5076: 5068: 5060: 5040: 5038: 5037: 5032: 5010: 5002: 4988: 4980: 4938: 4936: 4935: 4930: 4928: 4923: 4922: 4921: 4912: 4911: 4901: 4892: 4890: 4889: 4884: 4882: 4881: 4865: 4863: 4862: 4857: 4855: 4854: 4845: 4844: 4828: 4826: 4825: 4820: 4818: 4817: 4793: 4791: 4790: 4785: 4779: 4778: 4773: 4764: 4756: 4755: 4746: 4745: 4733: 4732: 4727: 4718: 4711: 4707: 4706: 4697: 4696: 4670: 4668: 4667: 4662: 4657: 4656: 4651: 4642: 4641: 4636: 4627: 4625: 4624: 4623: 4614: 4613: 4597: 4596: 4595: 4579: 4574: 4573: 4568: 4559: 4557: 4556: 4555: 4546: 4545: 4529: 4528: 4527: 4522: 4513: 4512: 4491: 4490: 4485: 4479: 4478: 4466: 4465: 4446: 4441: 4440: 4435: 4426: 4425: 4407: 4405: 4404: 4399: 4391: 4390: 4381: 4380: 4361: 4359: 4358: 4353: 4348: 4347: 4342: 4333: 4332: 4327: 4315: 4314: 4294: 4286: 4284: 4283: 4278: 4276: 4271: 4270: 4269: 4260: 4259: 4249: 4240: 4238: 4237: 4232: 4224: 4223: 4214: 4213: 4189: 4187: 4186: 4181: 4179: 4174: 4173: 4164: 4163: 4151: 4150: 4145: 4136: 4135: 4114: 4113: 4108: 4102: 4101: 4089: 4088: 4065: 4054: 4052: 4051: 4046: 4044: 4043: 4037: 4036: 4031: 4019: 4018: 4013: 4004: 3996: 3995: 3983: 3982: 3977: 3971: 3970: 3964: 3963: 3951: 3950: 3945: 3933: 3922: 3921: 3912: 3911: 3889: 3887: 3886: 3881: 3879: 3858: 3856: 3855: 3850: 3846: 3842: 3841: 3836: 3827: 3819: 3818: 3806: 3805: 3800: 3791: 3783: 3782: 3765: 3763: 3762: 3757: 3749: 3748: 3743: 3734: 3726: 3725: 3713: 3712: 3707: 3698: 3690: 3689: 3670: 3668: 3667: 3662: 3660: 3659: 3647: 3646: 3630: 3628: 3627: 3622: 3620: 3619: 3607: 3606: 3590: 3588: 3587: 3582: 3580: 3579: 3570: 3569: 3538: 3536: 3535: 3530: 3519: 3518: 3506: 3505: 3489: 3487: 3486: 3481: 3479: 3474: 3473: 3472: 3463: 3462: 3452: 3437: 3435: 3434: 3429: 3421: 3420: 3411: 3410: 3391: 3389: 3388: 3383: 3381: 3380: 3371: 3370: 3354: 3352: 3351: 3346: 3344: 3339: 3338: 3337: 3328: 3327: 3317: 3304: 3302: 3301: 3296: 3288: 3287: 3278: 3277: 3254: 3252: 3251: 3246: 3244: 3243: 3231: 3230: 3214: 3212: 3211: 3206: 3204: 3203: 3191: 3190: 3164: 3162: 3161: 3156: 3144: 3142: 3141: 3136: 3124: 3122: 3121: 3116: 3096: 3094: 3093: 3088: 3083: 3056: 3054: 3053: 3048: 3046: 3041: 3040: 3039: 3030: 3029: 3019: 3010: 3008: 3007: 3002: 3000: 2999: 2983: 2981: 2980: 2975: 2973: 2972: 2960: 2959: 2947: 2946: 2930: 2928: 2927: 2922: 2917: 2906: 2905: 2887: 2886: 2870: 2868: 2867: 2862: 2860: 2859: 2847: 2846: 2818: 2816: 2815: 2810: 2798: 2796: 2795: 2790: 2778: 2776: 2775: 2770: 2752: 2750: 2749: 2744: 2742: 2731: 2720: 2709: 2697: 2695: 2694: 2689: 2666:that the points 2661: 2659: 2658: 2653: 2651: 2646: 2645: 2633: 2628: 2623: 2615: 2614: 2605: 2597: 2592: 2591: 2579: 2574: 2569: 2564: 2563: 2551: 2535: 2533: 2532: 2527: 2515: 2513: 2512: 2507: 2492: 2490: 2489: 2484: 2469: 2467: 2466: 2461: 2459: 2454: 2453: 2441: 2436: 2431: 2426: 2425: 2413: 2395: 2393: 2392: 2387: 2375: 2373: 2372: 2367: 2355: 2353: 2352: 2347: 2342: 2337: 2336: 2327: 2326: 2317: 2312: 2309: 2295: 2289: 2284: 2283: 2271: 2259: 2257: 2256: 2251: 2249: 2244: 2243: 2231: 2220: 2215: 2214: 2202: 2190: 2188: 2187: 2182: 2180: 2175: 2174: 2162: 2151: 2146: 2145: 2133: 2121: 2119: 2118: 2113: 2092: 2090: 2089: 2084: 2069: 2067: 2066: 2061: 2059: 2058: 2042: 2040: 2039: 2034: 2020: 2019: 2007: 2006: 1937: 1935: 1934: 1929: 1927: 1926: 1914: 1913: 1897: 1895: 1894: 1889: 1887: 1886: 1874: 1873: 1857: 1855: 1854: 1849: 1847: 1842: 1841: 1840: 1827: 1818: 1816: 1815: 1810: 1808: 1803: 1802: 1801: 1792: 1791: 1781: 1772: 1770: 1769: 1764: 1762: 1761: 1745: 1743: 1742: 1737: 1735: 1734: 1715: 1713: 1712: 1707: 1705: 1704: 1688: 1686: 1685: 1680: 1678: 1677: 1661: 1659: 1658: 1653: 1651: 1650: 1634: 1632: 1631: 1626: 1624: 1623: 1607: 1605: 1604: 1599: 1548: 1546: 1545: 1540: 1515: 1513: 1512: 1507: 1505: 1500: 1492: 1487: 1482: 1474: 1466: 1461: 1450: 1442: 1430: 1428: 1427: 1422: 1420: 1415: 1407: 1402: 1390: 1388: 1387: 1382: 1380: 1365: 1344: 1342: 1341: 1336: 1324: 1322: 1321: 1316: 1314: 1300: 1286: 1275: 1261: 1249: 1247: 1246: 1241: 1239: 1224: 1222: 1221: 1216: 1214: 1203: 1195: 1183: 1181: 1180: 1175: 1163: 1161: 1160: 1155: 1153: 1142: 1130: 1128: 1127: 1122: 1047: 1046: 1037: 1036: 997:similitude ratio 982: 980: 979: 974: 962: 960: 959: 954: 952: 951: 946: 937: 925: 923: 922: 917: 915: 914: 894: 892: 891: 886: 884: 876: 860: 858: 857: 852: 794: 792: 791: 786: 768: 766: 765: 760: 731: 729: 728: 723: 707: 705: 704: 699: 694: 671: 669: 668: 663: 635: 633: 632: 627: 605: 603: 602: 597: 577: 575: 574: 569: 567: 556: 552: 536: 534: 533: 528: 506: 504: 503: 498: 493: 485: 471: 463: 459: 439: 437: 436: 431: 413: 411: 410: 405: 403: 398: 390: 382: 377: 376: 364: 352: 350: 349: 344: 342: 327: 325: 324: 319: 303: 301: 300: 295: 240: 238: 237: 232: 219:point reflection 216: 214: 213: 208: 186: 184: 183: 178: 149: 147: 146: 141: 118: 116: 115: 110: 86: 84: 83: 78: 59: 57: 56: 51: 21: 5877: 5876: 5872: 5871: 5870: 5868: 5867: 5866: 5852: 5851: 5838: 5822: 5809: 5798: 5792: 5787: 5779: 5775: 5767: 5763: 5759: 5699: 5665: 5664: 5659: 5654: 5648: 5647: 5627: 5622: 5616: 5615: 5595: 5590: 5580: 5574: 5573: 5569:by the matrix: 5547: 5546: 5487: 5486: 5464: 5463: 5426: 5425: 5365: 5364: 5361: 5337: 5336: 5312: 5284: 5279: 5278: 5239: 5212: 5208: 5189: 5166: 5165: 5091: 5090: 5045: 5044: 4965: 4964: 4913: 4903: 4902: 4895: 4894: 4873: 4868: 4867: 4846: 4836: 4831: 4830: 4809: 4804: 4803: 4768: 4747: 4737: 4722: 4698: 4688: 4683: 4682: 4646: 4631: 4615: 4605: 4598: 4587: 4580: 4563: 4547: 4537: 4530: 4517: 4504: 4480: 4470: 4457: 4447: 4430: 4417: 4412: 4411: 4382: 4372: 4367: 4366: 4337: 4322: 4306: 4289: 4288: 4261: 4251: 4250: 4243: 4242: 4215: 4205: 4200: 4199: 4165: 4155: 4140: 4127: 4103: 4093: 4080: 4058: 4057: 4026: 4008: 3987: 3972: 3955: 3940: 3913: 3903: 3895: 3894: 3864: 3863: 3831: 3810: 3795: 3774: 3769: 3768: 3738: 3717: 3702: 3681: 3676: 3675: 3651: 3638: 3633: 3632: 3611: 3598: 3593: 3592: 3571: 3561: 3556: 3555: 3510: 3497: 3492: 3491: 3464: 3454: 3453: 3446: 3445: 3412: 3402: 3397: 3396: 3372: 3362: 3357: 3356: 3329: 3319: 3318: 3311: 3310: 3279: 3269: 3264: 3263: 3235: 3222: 3217: 3216: 3215:and its ratios 3195: 3182: 3177: 3176: 3147: 3146: 3127: 3126: 3107: 3106: 3059: 3058: 3031: 3021: 3020: 3013: 3012: 2991: 2986: 2985: 2964: 2951: 2938: 2933: 2932: 2897: 2878: 2873: 2872: 2851: 2838: 2833: 2832: 2825: 2801: 2800: 2781: 2780: 2755: 2754: 2700: 2699: 2668: 2667: 2637: 2606: 2583: 2555: 2542: 2541: 2518: 2517: 2498: 2497: 2475: 2474: 2445: 2417: 2398: 2397: 2378: 2377: 2358: 2357: 2328: 2318: 2299: 2275: 2262: 2261: 2235: 2206: 2193: 2192: 2166: 2137: 2124: 2123: 2098: 2097: 2075: 2074: 2050: 2045: 2044: 2011: 1998: 1993: 1992: 1968: 1918: 1905: 1900: 1899: 1878: 1865: 1860: 1859: 1832: 1828: 1821: 1820: 1793: 1783: 1782: 1775: 1774: 1753: 1748: 1747: 1726: 1718: 1717: 1696: 1691: 1690: 1669: 1664: 1663: 1642: 1637: 1636: 1615: 1610: 1609: 1590: 1589: 1586: 1581: 1525: 1524: 1433: 1432: 1393: 1392: 1350: 1349: 1327: 1326: 1252: 1251: 1232: 1227: 1226: 1186: 1185: 1166: 1165: 1133: 1132: 1131:is the origin: 1113: 1112: 1069: 1061: 989:dilation factor 965: 964: 941: 928: 927: 926:and volumes by 906: 901: 900: 867: 866: 843: 842: 803:, the group of 771: 770: 745: 744: 714: 713: 682: 681: 645: 644: 612: 611: 588: 587: 584:uniform scaling 547: 542: 541: 513: 512: 454: 449: 448: 416: 415: 391: 369: 365: 358: 357: 335: 330: 329: 310: 309: 286: 285: 223: 222: 190: 189: 187: 163: 162: 126: 125: 123: 95: 94: 92: 63: 62: 60: 36: 35: 28: 23: 22: 15: 12: 11: 5: 5875: 5873: 5865: 5864: 5854: 5853: 5850: 5849: 5837: 5836:External links 5834: 5833: 5832: 5824:Tuller, Annita 5820: 5816:Addison-Wesley 5807: 5796: 5791: 5788: 5786: 5785: 5783:, p. 119) 5773: 5771:, p. 145) 5760: 5758: 5755: 5754: 5753: 5719: 5712: 5706: 5698: 5695: 5683: 5682: 5669: 5663: 5660: 5658: 5655: 5653: 5650: 5649: 5646: 5643: 5640: 5637: 5634: 5631: 5628: 5626: 5623: 5621: 5618: 5617: 5614: 5611: 5608: 5605: 5602: 5599: 5596: 5594: 5591: 5589: 5586: 5585: 5583: 5554: 5543: 5542: 5529: 5525: 5522: 5519: 5516: 5513: 5510: 5506: 5502: 5499: 5495: 5471: 5451: 5448: 5445: 5442: 5439: 5436: 5433: 5413: 5409: 5405: 5401: 5397: 5394: 5391: 5387: 5383: 5379: 5375: 5372: 5363:The homothety 5360: 5357: 5344: 5321: 5318: 5315: 5310: 5304: 5300: 5296: 5292: 5288: 5275: 5274: 5273: 5272: 5271: 5270: 5258: 5254: 5248: 5245: 5242: 5237: 5231: 5227: 5223: 5220: 5216: 5211: 5207: 5204: 5198: 5195: 5192: 5187: 5181: 5177: 5173: 5150: 5146: 5142: 5138: 5134: 5131: 5128: 5124: 5120: 5116: 5112: 5108: 5104: 5101: 5098: 5088: 5075: 5071: 5067: 5063: 5059: 5055: 5052: 5042: 5029: 5026: 5023: 5020: 5016: 5013: 5009: 5005: 5001: 4997: 4994: 4991: 4987: 4983: 4979: 4975: 4972: 4953: 4952: 4926: 4920: 4916: 4910: 4906: 4880: 4876: 4853: 4849: 4843: 4839: 4816: 4812: 4796: 4795: 4782: 4777: 4772: 4767: 4763: 4759: 4754: 4750: 4744: 4740: 4736: 4731: 4726: 4721: 4717: 4710: 4705: 4701: 4695: 4691: 4672: 4671: 4660: 4655: 4650: 4645: 4640: 4635: 4630: 4622: 4618: 4612: 4608: 4604: 4601: 4594: 4590: 4586: 4583: 4577: 4572: 4567: 4562: 4554: 4550: 4544: 4540: 4536: 4533: 4526: 4521: 4516: 4511: 4507: 4503: 4500: 4497: 4494: 4489: 4484: 4477: 4473: 4469: 4464: 4460: 4456: 4453: 4450: 4444: 4439: 4434: 4429: 4424: 4420: 4409: 4397: 4394: 4389: 4385: 4379: 4375: 4363: 4351: 4346: 4341: 4336: 4331: 4326: 4321: 4318: 4313: 4309: 4305: 4302: 4299: 4274: 4268: 4264: 4258: 4254: 4230: 4227: 4222: 4218: 4212: 4208: 4192: 4191: 4178: 4172: 4168: 4162: 4158: 4154: 4149: 4144: 4139: 4134: 4130: 4126: 4123: 4120: 4117: 4112: 4107: 4100: 4096: 4092: 4087: 4083: 4079: 4076: 4073: 4070: 4055: 4042: 4035: 4030: 4025: 4022: 4017: 4012: 4007: 4003: 3999: 3994: 3990: 3986: 3981: 3976: 3969: 3962: 3958: 3954: 3949: 3944: 3939: 3936: 3932: 3928: 3925: 3920: 3916: 3910: 3906: 3902: 3878: 3874: 3871: 3860: 3859: 3845: 3840: 3835: 3830: 3826: 3822: 3817: 3813: 3809: 3804: 3799: 3794: 3790: 3786: 3781: 3777: 3766: 3755: 3752: 3747: 3742: 3737: 3733: 3729: 3724: 3720: 3716: 3711: 3706: 3701: 3697: 3693: 3688: 3684: 3658: 3654: 3650: 3645: 3641: 3618: 3614: 3610: 3605: 3601: 3578: 3574: 3568: 3564: 3547: 3546: 3545: 3544: 3528: 3525: 3522: 3517: 3513: 3509: 3504: 3500: 3477: 3471: 3467: 3461: 3457: 3427: 3424: 3419: 3415: 3409: 3405: 3393: 3379: 3375: 3369: 3365: 3342: 3336: 3332: 3326: 3322: 3294: 3291: 3286: 3282: 3276: 3272: 3257: 3256: 3242: 3238: 3234: 3229: 3225: 3202: 3198: 3194: 3189: 3185: 3170: 3154: 3134: 3114: 3086: 3082: 3078: 3075: 3072: 3069: 3066: 3044: 3038: 3034: 3028: 3024: 2998: 2994: 2971: 2967: 2963: 2958: 2954: 2950: 2945: 2941: 2920: 2916: 2912: 2909: 2904: 2900: 2896: 2893: 2890: 2885: 2881: 2858: 2854: 2850: 2845: 2841: 2824: 2821: 2808: 2788: 2768: 2765: 2762: 2741: 2737: 2734: 2730: 2726: 2723: 2719: 2715: 2712: 2708: 2687: 2684: 2681: 2678: 2675: 2650: 2644: 2640: 2636: 2632: 2627: 2622: 2618: 2613: 2609: 2604: 2600: 2596: 2590: 2586: 2582: 2578: 2573: 2568: 2562: 2558: 2554: 2550: 2538: 2537: 2525: 2505: 2494: 2482: 2471: 2458: 2452: 2448: 2444: 2440: 2435: 2430: 2424: 2420: 2416: 2412: 2408: 2405: 2385: 2365: 2345: 2341: 2335: 2331: 2325: 2321: 2316: 2308: 2305: 2302: 2298: 2292: 2288: 2282: 2278: 2274: 2270: 2248: 2242: 2238: 2234: 2230: 2226: 2223: 2219: 2213: 2209: 2205: 2201: 2179: 2173: 2169: 2165: 2161: 2157: 2154: 2150: 2144: 2140: 2136: 2132: 2111: 2108: 2105: 2094: 2082: 2057: 2053: 2032: 2029: 2026: 2023: 2018: 2014: 2010: 2005: 2001: 1991:with vertices 1967: 1964: 1925: 1921: 1917: 1912: 1908: 1885: 1881: 1877: 1872: 1868: 1845: 1839: 1835: 1831: 1806: 1800: 1796: 1790: 1786: 1760: 1756: 1733: 1729: 1725: 1703: 1699: 1676: 1672: 1649: 1645: 1622: 1618: 1597: 1585: 1582: 1580: 1577: 1538: 1535: 1532: 1504: 1499: 1495: 1491: 1486: 1481: 1477: 1473: 1469: 1465: 1460: 1456: 1453: 1449: 1445: 1441: 1419: 1414: 1410: 1406: 1401: 1379: 1375: 1372: 1368: 1364: 1360: 1357: 1334: 1313: 1309: 1306: 1303: 1299: 1295: 1292: 1289: 1285: 1281: 1278: 1274: 1270: 1267: 1264: 1260: 1250:with equation 1238: 1235: 1213: 1209: 1206: 1202: 1198: 1194: 1173: 1152: 1148: 1145: 1141: 1120: 1106: 1105: 1092: 1091: 1084: 1068: 1065: 1060: 1057: 1026:Michel Chasles 972: 950: 945: 940: 936: 913: 909: 883: 879: 875: 850: 784: 781: 778: 758: 755: 752: 721: 697: 693: 689: 678: 677: 676:at the center, 661: 658: 655: 652: 641: 625: 622: 619: 595: 580: 579: 566: 562: 559: 555: 551: 526: 523: 520: 509: 508: 496: 492: 488: 484: 480: 477: 474: 470: 466: 462: 458: 442: 441: 429: 426: 423: 401: 397: 394: 388: 385: 380: 375: 372: 368: 341: 338: 317: 293: 270:transformation 230: 206: 203: 200: 197: 176: 173: 170: 139: 136: 133: 108: 105: 102: 76: 73: 70: 49: 46: 43: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 5874: 5863: 5860: 5859: 5857: 5847: 5843: 5840: 5839: 5835: 5829: 5825: 5821: 5817: 5813: 5808: 5805: 5801: 5797: 5794: 5793: 5789: 5782: 5777: 5774: 5770: 5765: 5762: 5756: 5751: 5747: 5743: 5739: 5735: 5731: 5727: 5723: 5720: 5717: 5713: 5710: 5707: 5704: 5701: 5700: 5696: 5694: 5692: 5688: 5667: 5661: 5656: 5651: 5644: 5638: 5635: 5632: 5624: 5619: 5612: 5606: 5603: 5600: 5592: 5587: 5581: 5572: 5571: 5570: 5568: 5552: 5520: 5517: 5514: 5508: 5500: 5485: 5484: 5483: 5469: 5446: 5443: 5440: 5434: 5431: 5403: 5392: 5389: 5373: 5370: 5358: 5356: 5342: 5319: 5316: 5313: 5302: 5294: 5290: 5256: 5246: 5243: 5240: 5229: 5218: 5209: 5205: 5202: 5196: 5193: 5190: 5179: 5171: 5164: 5163: 5162: 5161: 5140: 5129: 5126: 5118: 5102: 5099: 5096: 5089: 5069: 5053: 5050: 5043: 5027: 5024: 5021: 5018: 5014: 5003: 4992: 4989: 4973: 4970: 4963: 4962: 4961: 4958: 4957: 4950: 4949: 4944: 4940: 4918: 4914: 4908: 4904: 4893:lies on line 4878: 4874: 4851: 4847: 4841: 4837: 4814: 4810: 4801: 4775: 4765: 4752: 4748: 4742: 4738: 4734: 4729: 4708: 4703: 4699: 4693: 4689: 4681: 4680: 4679: 4677: 4653: 4643: 4638: 4620: 4616: 4610: 4606: 4602: 4599: 4592: 4588: 4584: 4581: 4575: 4570: 4560: 4552: 4548: 4542: 4538: 4534: 4531: 4524: 4509: 4505: 4501: 4498: 4492: 4487: 4475: 4471: 4462: 4458: 4454: 4451: 4442: 4437: 4427: 4422: 4418: 4410: 4395: 4392: 4387: 4383: 4377: 4373: 4364: 4344: 4334: 4329: 4311: 4307: 4303: 4300: 4272: 4266: 4262: 4256: 4252: 4228: 4225: 4220: 4216: 4210: 4206: 4197: 4196: 4195: 4170: 4166: 4160: 4156: 4152: 4147: 4132: 4128: 4124: 4121: 4115: 4110: 4098: 4094: 4085: 4081: 4077: 4074: 4068: 4056: 4033: 4023: 4015: 4005: 3992: 3988: 3984: 3979: 3960: 3956: 3952: 3947: 3937: 3918: 3914: 3908: 3904: 3893: 3892: 3891: 3872: 3869: 3838: 3828: 3815: 3811: 3807: 3802: 3784: 3779: 3775: 3767: 3753: 3745: 3735: 3722: 3718: 3714: 3709: 3691: 3686: 3682: 3674: 3673: 3672: 3656: 3652: 3648: 3643: 3639: 3631:with centers 3616: 3612: 3608: 3603: 3599: 3576: 3572: 3566: 3562: 3552: 3551: 3542: 3526: 3523: 3520: 3515: 3511: 3507: 3502: 3498: 3475: 3469: 3465: 3459: 3455: 3444:in direction 3443: 3442: 3425: 3422: 3417: 3413: 3407: 3403: 3394: 3377: 3373: 3367: 3363: 3334: 3330: 3324: 3320: 3308: 3292: 3289: 3284: 3280: 3274: 3270: 3261: 3260: 3259: 3258: 3240: 3236: 3232: 3227: 3223: 3200: 3196: 3192: 3187: 3183: 3175: 3171: 3168: 3152: 3132: 3112: 3105: 3101: 3100: 3084: 3080: 3076: 3073: 3070: 3067: 3064: 3036: 3032: 3026: 3022: 2996: 2992: 2969: 2965: 2956: 2952: 2943: 2939: 2918: 2914: 2910: 2907: 2902: 2898: 2894: 2891: 2888: 2883: 2879: 2856: 2852: 2848: 2843: 2839: 2829: 2822: 2820: 2806: 2786: 2766: 2760: 2735: 2732: 2724: 2721: 2713: 2710: 2685: 2682: 2679: 2676: 2673: 2665: 2642: 2638: 2634: 2625: 2616: 2611: 2607: 2598: 2588: 2584: 2580: 2571: 2560: 2556: 2552: 2523: 2503: 2495: 2480: 2472: 2450: 2446: 2442: 2433: 2422: 2418: 2414: 2406: 2403: 2383: 2363: 2343: 2333: 2329: 2323: 2319: 2306: 2303: 2300: 2296: 2290: 2280: 2276: 2272: 2240: 2236: 2232: 2224: 2221: 2211: 2207: 2203: 2171: 2167: 2163: 2155: 2152: 2142: 2138: 2134: 2109: 2106: 2103: 2095: 2080: 2073: 2055: 2051: 2030: 2027: 2024: 2021: 2016: 2012: 2008: 2003: 1999: 1990: 1989:parallelogram 1986: 1985: 1984: 1983: 1979: 1977: 1973: 1965: 1959: 1951: 1943: 1939: 1923: 1919: 1915: 1910: 1906: 1883: 1879: 1875: 1870: 1866: 1837: 1833: 1829: 1798: 1794: 1788: 1784: 1758: 1754: 1731: 1727: 1723: 1701: 1697: 1674: 1670: 1647: 1643: 1620: 1616: 1595: 1583: 1578: 1574: 1569: 1565: 1563: 1559: 1555: 1550: 1536: 1533: 1530: 1521: 1519: 1493: 1475: 1467: 1454: 1451: 1443: 1408: 1373: 1370: 1366: 1358: 1355: 1346: 1332: 1307: 1304: 1301: 1293: 1290: 1279: 1276: 1265: 1262: 1236: 1233: 1207: 1204: 1196: 1171: 1146: 1118: 1110: 1103: 1102: 1097: 1096: 1095: 1090:is preserved. 1089: 1085: 1082: 1078: 1074: 1073: 1072: 1066: 1064: 1058: 1056: 1053: 1051: 1050:Russian dolls 1041: 1031: 1027: 1022: 1020: 1016: 1012: 1011: 1006: 1002: 998: 994: 990: 986: 970: 948: 938: 911: 907: 898: 877: 864: 848: 839: 837: 833: 828: 826: 822: 818: 814: 810: 806: 802: 798: 782: 779: 776: 756: 753: 750: 742: 738: 733: 719: 711: 708:one gets the 695: 691: 687: 675: 672:one gets the 659: 656: 653: 650: 642: 639: 636:one gets the 623: 620: 617: 609: 608: 607: 593: 585: 560: 557: 553: 540: 539: 538: 524: 521: 518: 486: 475: 472: 464: 460: 447: 446: 445: 427: 424: 421: 399: 395: 392: 386: 383: 378: 373: 370: 366: 356: 355: 354: 353:by the rule 339: 336: 315: 307: 291: 283: 279: 275: 271: 267: 263: 259: 255: 246: 228: 220: 204: 201: 198: 195: 174: 171: 168: 161:Example with 159: 153: 137: 134: 131: 122: 106: 103: 100: 90: 87:one gets the 74: 71: 68: 47: 44: 41: 32: 19: 5846:Cut-the-Knot 5827: 5811: 5803: 5800:Hadamard, J. 5781:Tuller (1967 5776: 5764: 5745: 5737: 5736:)) in which 5733: 5729: 5725: 5684: 5544: 5424:with center 5362: 5276: 4959: 4955: 4954: 4802:with center 4799: 4797: 4675: 4673: 4193: 3861: 3553: 3549: 3548: 3439: 3306: 3173: 3103: 3057:with ratio 2871:and ratios 2663: 2539: 2356:(Instead of 2071: 1988: 1981: 1980: 1969: 1587: 1551: 1522: 1517: 1347: 1108: 1107: 1099: 1093: 1087: 1080: 1076: 1070: 1062: 1054: 1039: 1029: 1023: 1018: 1014: 1008: 1004: 1000: 996: 993:scale factor 992: 988: 984: 896: 862: 840: 829: 824: 816: 808: 804: 797:translations 741:similarities 734: 709: 679: 673: 637: 581: 510: 443: 305: 281: 277: 274:affine space 265: 261: 257: 251: 217:one gets a 151: 120: 88: 4956:Derivation: 4365:in case of 4198:in case of 3550:Derivation: 3441:translation 3395:in case of 3262:in case of 3104:same center 2823:Composition 2540:Because of 1635:of a point 1523:In case of 1001:enlargement 861:multiplies 582:which is a 511:In case of 328:to a point 304:called its 280:called its 254:mathematics 121:enlargement 18:Homotheties 5790:References 5335:and ratio 4829:and ratio 4287:by vector 3355:and ratio 2799:and ratio 2122:such that 1972:pantograph 1945:Pantograph 1608:the image 1164:. A line 1101:similarity 1059:Properties 1007:is called 819:is a line 674:reflection 537:(Origin): 5842:Homothety 5691:conformal 5636:− 5604:− 5553:σ 5518:− 5498:→ 5404:− 5382:→ 5371:σ 5317:− 5244:− 5219:− 5194:− 5141:− 5111:→ 5100:σ 5097:τ 5062:→ 5051:τ 5022:≠ 5004:− 4982:→ 4971:σ 4925:¯ 4800:homothety 4766:− 4720:→ 4700:σ 4690:σ 4644:− 4603:− 4585:− 4535:− 4502:− 4455:− 4393:≠ 4335:− 4304:− 4273:→ 4125:− 4078:− 4024:− 4006:− 3915:σ 3905:σ 3829:− 3793:→ 3776:σ 3736:− 3700:→ 3683:σ 3613:σ 3600:σ 3573:σ 3563:σ 3524:− 3476:→ 3341:¯ 3307:homothety 3290:≠ 3068:⋅ 3043:¯ 2962:→ 2949:→ 2764:→ 2304:− 1844:¯ 1805:¯ 1534:≠ 1494:− 1452:− 1409:− 1144:→ 863:distances 836:invariant 805:dilations 657:− 487:− 425:≠ 400:→ 379:→ 262:homothecy 258:homothety 221:at point 202:− 152:reduction 5856:Category 5826:(1967), 5769:Hadamard 5697:See also 5689:is also 5291:′ 4676:fixpoint 3011:on line 2931:mapping 1237:′ 963:. Here 821:parallel 640:mapping, 638:identity 554:′ 461:′ 374:′ 340:′ 89:identity 3165:form a 1976:compass 1562:ellipse 1554:similar 983:is the 710:inverse 268:) is a 5545:Hence 4712:  4295:  4066:  3847:  1558:circle 1081:angles 1040:thesis 282:center 272:of an 5757:Notes 5748:is a 5740:is a 4798:is a 4674:is a 4408:point 3671:with 3167:group 2072:ratio 1571:With 1518:ratio 1045:Θέσις 1030:homo- 897:areas 801:group 306:ratio 264:, or 5744:and 5714:The 2191:and 1819:and 1431:and 1086:The 1077:line 780:< 754:> 680:For 643:for 610:for 260:(or 256:, a 188:For 172:< 135:< 124:for 104:> 93:for 61:For 45:> 1391:is 1035:όμο 1017:or 1013:or 995:or 991:or 987:or 899:by 830:In 823:to 807:or 735:In 252:In 119:an 5858:: 5814:, 5802:, 5355:. 5087:is 4939:. 4866:. 3890:: 3543:). 3438:a 3392:or 3305:a 3255:is 2819:. 2470:.) 1978:. 1938:. 1345:. 1075:A 1021:. 895:, 838:. 827:. 732:. 606:: 150:a 5848:. 5752:. 5746:f 5738:U 5734:y 5732:( 5730:U 5728:( 5726:f 5668:) 5662:1 5657:0 5652:0 5645:v 5642:) 5639:k 5633:1 5630:( 5625:k 5620:0 5613:u 5610:) 5607:k 5601:1 5598:( 5593:0 5588:k 5582:( 5541:. 5528:s 5524:) 5521:k 5515:1 5512:( 5509:+ 5505:x 5501:k 5494:x 5470:O 5450:) 5447:v 5444:, 5441:u 5438:( 5435:= 5432:S 5412:) 5408:s 5400:x 5396:( 5393:k 5390:+ 5386:s 5378:x 5374:: 5343:k 5320:k 5314:1 5309:v 5303:+ 5299:s 5295:= 5287:s 5257:) 5253:) 5247:k 5241:1 5236:v 5230:+ 5226:s 5222:( 5215:x 5210:( 5206:k 5203:+ 5197:k 5191:1 5186:v 5180:+ 5176:s 5172:= 5149:) 5145:s 5137:x 5133:( 5130:k 5127:+ 5123:v 5119:+ 5115:s 5107:x 5103:: 5074:v 5070:+ 5066:x 5058:x 5054:: 5028:, 5025:1 5019:k 5015:, 5012:) 5008:s 5000:x 4996:( 4993:k 4990:+ 4986:s 4978:x 4974:: 4919:2 4915:S 4909:1 4905:S 4879:3 4875:S 4852:2 4848:k 4842:1 4838:k 4815:3 4811:S 4794:. 4781:) 4776:3 4771:s 4762:x 4758:( 4753:2 4749:k 4743:1 4739:k 4735:+ 4730:3 4725:s 4716:x 4709:: 4704:1 4694:2 4659:) 4654:1 4649:s 4639:2 4634:s 4629:( 4621:2 4617:k 4611:1 4607:k 4600:1 4593:2 4589:k 4582:1 4576:+ 4571:1 4566:s 4561:= 4553:2 4549:k 4543:1 4539:k 4532:1 4525:2 4520:s 4515:) 4510:2 4506:k 4499:1 4496:( 4493:+ 4488:1 4483:s 4476:2 4472:k 4468:) 4463:1 4459:k 4452:1 4449:( 4443:= 4438:3 4433:s 4428:: 4423:3 4419:S 4396:1 4388:2 4384:k 4378:1 4374:k 4362:. 4350:) 4345:1 4340:s 4330:2 4325:s 4320:( 4317:) 4312:2 4308:k 4301:1 4298:( 4267:2 4263:S 4257:1 4253:S 4229:1 4226:= 4221:2 4217:k 4211:1 4207:k 4190:. 4177:x 4171:2 4167:k 4161:1 4157:k 4153:+ 4148:2 4143:s 4138:) 4133:2 4129:k 4122:1 4119:( 4116:+ 4111:1 4106:s 4099:2 4095:k 4091:) 4086:1 4082:k 4075:1 4072:( 4069:= 4041:) 4034:2 4029:s 4021:) 4016:1 4011:s 4002:x 3998:( 3993:1 3989:k 3985:+ 3980:1 3975:s 3968:( 3961:2 3957:k 3953:+ 3948:2 3943:s 3938:= 3935:) 3931:x 3927:( 3924:) 3919:1 3909:2 3901:( 3877:x 3873:: 3870:X 3844:) 3839:2 3834:s 3825:x 3821:( 3816:2 3812:k 3808:+ 3803:2 3798:s 3789:x 3785:: 3780:2 3754:, 3751:) 3746:1 3741:s 3732:x 3728:( 3723:1 3719:k 3715:+ 3710:1 3705:s 3696:x 3692:: 3687:1 3657:2 3653:S 3649:, 3644:1 3640:S 3617:2 3609:, 3604:1 3577:1 3567:2 3539:( 3527:1 3521:= 3516:2 3512:k 3508:= 3503:1 3499:k 3470:2 3466:S 3460:1 3456:S 3426:1 3423:= 3418:2 3414:k 3408:1 3404:k 3378:2 3374:k 3368:1 3364:k 3335:2 3331:S 3325:1 3321:S 3293:1 3285:2 3281:k 3275:1 3271:k 3241:2 3237:k 3233:, 3228:1 3224:k 3201:2 3197:S 3193:, 3188:1 3184:S 3169:. 3153:S 3133:S 3113:S 3097:. 3085:6 3081:. 3077:0 3074:= 3071:l 3065:k 3037:2 3033:S 3027:1 3023:S 2997:3 2993:S 2970:i 2966:R 2957:i 2953:Q 2944:i 2940:P 2919:3 2915:. 2911:0 2908:= 2903:2 2899:k 2895:, 2892:2 2889:= 2884:1 2880:k 2857:2 2853:S 2849:, 2844:1 2840:S 2807:k 2787:S 2767:Q 2761:P 2740:| 2736:P 2733:S 2729:| 2725:k 2722:= 2718:| 2714:Q 2711:S 2707:| 2686:Q 2683:, 2680:P 2677:, 2674:S 2649:| 2643:0 2639:P 2635:P 2631:| 2626:/ 2621:| 2617:Q 2612:0 2608:Q 2603:| 2599:= 2595:| 2589:0 2585:P 2581:S 2577:| 2572:/ 2567:| 2561:0 2557:Q 2553:S 2549:| 2536:. 2524:Q 2504:P 2493:. 2481:S 2457:| 2451:0 2447:P 2443:S 2439:| 2434:/ 2429:| 2423:0 2419:Q 2415:S 2411:| 2407:= 2404:k 2384:S 2364:k 2344:. 2340:| 2334:0 2330:Q 2324:0 2320:P 2315:| 2307:1 2301:k 2297:k 2291:= 2287:| 2281:0 2277:Q 2273:S 2269:| 2247:| 2241:0 2237:Q 2233:H 2229:| 2225:k 2222:= 2218:| 2212:0 2208:Q 2204:Q 2200:| 2178:| 2172:0 2168:P 2164:S 2160:| 2156:k 2153:= 2149:| 2143:0 2139:Q 2135:S 2131:| 2110:Q 2107:, 2104:S 2093:. 2081:k 2056:0 2052:Q 2031:P 2028:, 2025:H 2022:, 2017:0 2013:Q 2009:, 2004:0 2000:P 1924:2 1920:Q 1916:, 1911:2 1907:P 1884:1 1880:Q 1876:, 1871:1 1867:P 1838:2 1834:P 1830:S 1799:2 1795:P 1789:1 1785:P 1759:2 1755:Q 1732:1 1728:P 1724:S 1702:2 1698:P 1675:2 1671:Q 1648:1 1644:P 1621:1 1617:Q 1596:S 1537:O 1531:S 1503:| 1498:q 1490:p 1485:| 1480:| 1476:k 1472:| 1468:= 1464:| 1459:q 1455:k 1448:p 1444:k 1440:| 1418:| 1413:q 1405:p 1400:| 1378:q 1374:: 1371:Q 1367:, 1363:p 1359:: 1356:P 1333:g 1312:v 1308:k 1305:t 1302:+ 1298:p 1294:k 1291:= 1288:) 1284:v 1280:t 1277:+ 1273:p 1269:( 1266:k 1263:= 1259:x 1234:g 1212:v 1208:t 1205:+ 1201:p 1197:= 1193:x 1172:g 1151:x 1147:k 1140:x 1119:S 1104:. 1042:( 1032:( 1005:S 971:k 949:3 944:| 939:k 935:| 912:2 908:k 882:| 878:k 874:| 849:k 825:g 817:g 783:0 777:k 757:0 751:k 720:k 696:k 692:/ 688:1 660:1 654:= 651:k 624:1 621:= 618:k 594:k 578:, 565:x 561:k 558:= 550:x 525:O 522:= 519:S 507:. 495:) 491:s 483:x 479:( 476:k 473:+ 469:s 465:= 457:x 440:. 428:0 422:k 396:X 393:S 387:k 384:= 371:X 367:S 337:X 316:X 292:k 278:S 229:S 205:1 199:= 196:k 175:0 169:k 138:1 132:k 107:1 101:k 75:1 72:= 69:k 48:0 42:k 20:)

Index

Homotheties


point reflection

mathematics
transformation
affine space
uniform scaling
Euclidean geometry
similarities
translations
group
affine transformations
parallel
projective geometry
invariant
homothetic center
Michel Chasles
Russian dolls
similarity
similar
circle
ellipse

intercept theorem



pantograph

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