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Decagram (geometry)

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has two vertices and one edge. There are isotoxal decagram forms, which alternates vertices at two radii. Each form has a freedom of one angle. The first is a variation of a double-wound of a pentagon {5}, and last is a variation of a double-wound of a pentagram {5/2}. The middle is a variation of a
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Coxeter, The Densities of the Regular polytopes I, p.43 If d is odd, the truncation of the polygon {p/q} is naturally {2n/d}. But if not, it consists of two coincident {n/(d/2)}'s; two, because each side arises from an original side and once from an original vertex. Thus the density of a polygon is
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Deeper truncations of the regular pentagon and pentagram can produce intermediate star polygon forms with ten equally spaced vertices and two edge lengths that remain
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through similar reasons. It has six four-dimensional analogues, with two of these being compounds of two self-dual star polytopes, like the pentagram itself; the
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The Lighter Side of Mathematics: Proceedings of the EugĂšne Strens Memorial Conference on Recreational Mathematics and its History, (1994),
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For a regular decagram with unit edge lengths, the proportions of the crossing points on each edge are as shown below.
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Sarhangi, Reza (2012), "Polyhedral Modularity in a Special Class of Decagram Based Interlocking Star Polygons",
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Philosophical Transactions of the Royal Society of London. Series A. Mathematical and Physical Sciences
296: 75: 1106: 1031: 1483: 1056: 941: 476:, but there are also three ten-vertex polygrams which can be interpreted as regular compounds: 264: 1457: 1397: 1036: 786: 743: 1478: 1341: 1111: 1041: 983: 898: 862: 236: 42: 8: 1447: 1422: 1392: 1387: 1061: 592: 465: 172: 866: 1452: 993: 902: 886: 832: 472:. Only one of these polygrams, {10/3} (connecting every third point), forms a regular 320: 291: 63: 1432: 1026: 934: 906: 878: 858: 749: 622: 134: 53: 961: 870: 625:(any two vertices can be transformed into each other by a symmetry of the figure). 407: 1427: 1407: 1402: 1372: 1091: 1066: 998: 894: 664: 657: 648: 418: 316: 180: 176: 49: 698: 691: 682: 444: 1437: 1417: 1382: 1377: 1008: 988: 341: 331: 168: 150: 146: 598:{10/4} can be seen as the two-dimensional equivalent of the three-dimensional 1472: 1412: 1263: 1156: 1076: 1018: 882: 554: 547: 533: 540: 28: 1442: 1312: 1268: 1232: 1222: 1217: 874: 671: 473: 312: 201: 187: 164: 1351: 1258: 1237: 1227: 805:
Regular polytopes, p 93-95, regular star polygons, regular star compounds
386: 246: 849:; Longuet-Higgins, M. S.; Miller, J. C. P. (1954). "Uniform polyhedra". 468:, represented by symbol {10/n}, containing the same vertices as regular 1356: 1212: 1202: 1086: 251: 346: 336: 1331: 1321: 1298: 1288: 1278: 1207: 1116: 1081: 890: 526: 488: 226: 216: 705: 431: 1336: 1326: 1283: 1242: 1171: 1161: 1151: 970: 495: 374: 304: 231: 221: 926: 1293: 1273: 1186: 1181: 1176: 1166: 1141: 1096: 957: 469: 1101: 600:
compound of small stellated dodecahedron and great dodecahedron
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compound of great icosahedron and great stellated dodecahedron
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Bridges 2012: Mathematics, Music, Art, Architecture, Culture
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Decagrams have been used as one of the decorative motifs in
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Coxeter, Introduction to Geometry, second edition, 2.8
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List of regular polytopes and compounds § Stars
583:{10/2} can be seen as the 2D equivalent of the 3D 1470: 629:Isogonal truncations of pentagon and pentagram 942: 272: 949: 935: 319:, but connected by every third point. Its 279: 265: 679: 645: 612:compound of two grand stellated 120-cells 520: 784: 585:compound of dodecahedron and icosahedron 480:{10/5} is a compound of five degenerate 299:, here in a Quran from the 14th century. 290: 1471: 771:, Henry George Liddell, Robert Scott, 741: 616:Polytope compound#Compounds with duals 401: 930: 595:in their respective dual positions. 956: 365: 13: 459: 14: 1495: 589:compound of 120-cell and 600-cell 464:A regular decagram is a 10-sided 704: 697: 690: 681: 670: 663: 656: 647: 553: 546: 539: 532: 525: 443: 430: 417: 393: 373: 119: 114: 109: 101: 96: 91: 86: 81: 27: 847:Coxeter, Harold Scott MacDonald 703: 680: 669: 646: 608:compound of two great 120-cells 591:; that is, the compound of two 545: 538: 531: 524: 380: 913: 838: 821: 808: 799: 778: 762: 735: 1: 728: 614:. A full list can be seen at 521: 748:, Springer, pp. 28–29, 560: 501: 494:{10/2} is a compound of two 487:{10/4} is a compound of two 415: 7: 716: 10: 1500: 411:regular decagram, {10/3}. 297:Islamic geometric patterns 1365: 1311: 1251: 1195: 1134: 1125: 1017: 969: 829:Metamorphoses of polygons 676:t{5/4} = {10/4} = 2{5/2} 636: 516: 186: 160: 145: 128: 74: 62: 48: 38: 26: 21: 920:unaltered by truncation. 295:Decagrams are common in 773:A Greek-English Lexicon 710:t{5/2} = {10/2} = 2{5} 76:Coxeter–Dynkin diagrams 16:10-pointed star polygon 875:10.1098/rsta.1954.0003 300: 742:Barnes, John (2012), 294: 1182:Nonagon/Enneagon (9) 1112:Tangential trapezoid 593:pentagonal polytopes 354:suffix derives from 43:Regular star polygon 1294:Megagon (1,000,000) 1062:Isosceles trapezoid 867:1954RSPTA.246..401C 630: 402:Isotoxal variations 1264:Icositetragon (24) 794:, pp. 165–174 628: 362:) meaning a line. 301: 33:A regular decagram 1466: 1465: 1307: 1306: 1284:Myriagon (10,000) 1269:Triacontagon (30) 1233:Heptadecagon (17) 1223:Pentadecagon (15) 1218:Tetradecagon (14) 1157:Quadrilateral (4) 1027:Antiparallelogram 859:The Royal Society 714: 713: 623:vertex-transitive 581: 580: 457: 456: 289: 288: 196: 195: 1491: 1279:Chiliagon (1000) 1259:Icositrigon (23) 1238:Octadecagon (18) 1228:Hexadecagon (16) 1132: 1131: 951: 944: 937: 928: 927: 921: 917: 911: 910: 842: 836: 825: 819: 812: 806: 803: 797: 795: 793: 782: 776: 766: 760: 758: 745:Gems of Geometry 739: 708: 701: 694: 687:t{5/3} = {10/3} 685: 674: 667: 660: 651: 642:Double covering 631: 627: 574:{10/4} = 2{5/2} 557: 550: 543: 536: 529: 502: 447: 434: 421: 414: 413: 408:isotoxal polygon 397: 377: 366:Regular decagram 281: 274: 267: 198: 197: 124: 123: 122: 118: 117: 113: 112: 106: 105: 104: 100: 99: 95: 94: 90: 89: 85: 84: 31: 22:Regular decagram 19: 18: 1499: 1498: 1494: 1493: 1492: 1490: 1489: 1488: 1469: 1468: 1467: 1462: 1361: 1315: 1303: 1247: 1213:Tridecagon (13) 1203:Hendecagon (11) 1191: 1127: 1121: 1092:Right trapezoid 1013: 965: 955: 925: 924: 918: 914: 843: 839: 833:Branko GrĂŒnbaum 826: 822: 813: 809: 804: 800: 791: 783: 779: 767: 763: 756: 740: 736: 731: 719: 709: 686: 675: 652: 641: 462: 460:Related figures 452: 448: 439: 435: 426: 422: 404: 383: 368: 321:SchlĂ€fli symbol 317:regular decagon 285: 256: 208: 140: 120: 115: 110: 108: 107: 102: 97: 92: 87: 82: 80: 69: 64:SchlĂ€fli symbol 34: 17: 12: 11: 5: 1497: 1487: 1486: 1481: 1464: 1463: 1461: 1460: 1455: 1450: 1445: 1440: 1435: 1430: 1425: 1420: 1418:Pseudotriangle 1415: 1410: 1405: 1400: 1395: 1390: 1385: 1380: 1375: 1369: 1367: 1363: 1362: 1360: 1359: 1354: 1349: 1344: 1339: 1334: 1329: 1324: 1318: 1316: 1309: 1308: 1305: 1304: 1302: 1301: 1296: 1291: 1286: 1281: 1276: 1271: 1266: 1261: 1255: 1253: 1249: 1248: 1246: 1245: 1240: 1235: 1230: 1225: 1220: 1215: 1210: 1208:Dodecagon (12) 1205: 1199: 1197: 1193: 1192: 1190: 1189: 1184: 1179: 1174: 1169: 1164: 1159: 1154: 1149: 1144: 1138: 1136: 1129: 1123: 1122: 1120: 1119: 1114: 1109: 1104: 1099: 1094: 1089: 1084: 1079: 1074: 1069: 1064: 1059: 1054: 1049: 1044: 1039: 1034: 1029: 1023: 1021: 1019:Quadrilaterals 1015: 1014: 1012: 1011: 1006: 1001: 996: 991: 986: 981: 975: 973: 967: 966: 954: 953: 946: 939: 931: 923: 922: 912: 837: 820: 807: 798: 777: 761: 754: 733: 732: 730: 727: 726: 725: 718: 715: 712: 711: 702: 695: 688: 678: 677: 668: 661: 654: 644: 643: 638: 635: 579: 578: 577:{10/5} = 5{2} 575: 572: 569: 568:{10/2} = 2{5} 566: 565:{10/1} = {10} 563: 559: 558: 551: 544: 537: 530: 523: 519: 518: 515: 512: 509: 506: 500: 499: 492: 485: 461: 458: 455: 454: 450: 441: 437: 428: 424: 403: 400: 399: 398: 382: 379: 367: 364: 332:numeral prefix 311:is a 10-point 287: 286: 284: 283: 276: 269: 261: 258: 257: 255: 254: 249: 244: 239: 234: 229: 224: 219: 213: 210: 209: 205: 204: 194: 193: 190: 184: 183: 162: 158: 157: 154: 147:Internal angle 143: 142: 138: 132: 130:Symmetry group 126: 125: 78: 72: 71: 66: 60: 59: 56: 46: 45: 40: 36: 35: 32: 24: 23: 15: 9: 6: 4: 3: 2: 1496: 1485: 1484:Star polygons 1482: 1480: 1477: 1476: 1474: 1459: 1458:Weakly simple 1456: 1454: 1451: 1449: 1446: 1444: 1441: 1439: 1436: 1434: 1431: 1429: 1426: 1424: 1421: 1419: 1416: 1414: 1411: 1409: 1406: 1404: 1401: 1399: 1398:Infinite skew 1396: 1394: 1391: 1389: 1386: 1384: 1381: 1379: 1376: 1374: 1371: 1370: 1368: 1364: 1358: 1355: 1353: 1350: 1348: 1345: 1343: 1340: 1338: 1335: 1333: 1330: 1328: 1325: 1323: 1320: 1319: 1317: 1314: 1313:Star polygons 1310: 1300: 1299:Apeirogon (∞) 1297: 1295: 1292: 1290: 1287: 1285: 1282: 1280: 1277: 1275: 1272: 1270: 1267: 1265: 1262: 1260: 1257: 1256: 1254: 1250: 1244: 1243:Icosagon (20) 1241: 1239: 1236: 1234: 1231: 1229: 1226: 1224: 1221: 1219: 1216: 1214: 1211: 1209: 1206: 1204: 1201: 1200: 1198: 1194: 1188: 1185: 1183: 1180: 1178: 1175: 1173: 1170: 1168: 1165: 1163: 1160: 1158: 1155: 1153: 1150: 1148: 1145: 1143: 1140: 1139: 1137: 1133: 1130: 1124: 1118: 1115: 1113: 1110: 1108: 1105: 1103: 1100: 1098: 1095: 1093: 1090: 1088: 1085: 1083: 1080: 1078: 1077:Parallelogram 1075: 1073: 1072:Orthodiagonal 1070: 1068: 1065: 1063: 1060: 1058: 1055: 1053: 1052:Ex-tangential 1050: 1048: 1045: 1043: 1040: 1038: 1035: 1033: 1030: 1028: 1025: 1024: 1022: 1020: 1016: 1010: 1007: 1005: 1002: 1000: 997: 995: 992: 990: 987: 985: 982: 980: 977: 976: 974: 972: 968: 963: 959: 952: 947: 945: 940: 938: 933: 932: 929: 916: 908: 904: 900: 896: 892: 888: 884: 880: 876: 872: 868: 864: 860: 856: 852: 848: 841: 834: 830: 824: 817: 816:Star polygons 811: 802: 790: 789: 781: 774: 770: 765: 757: 755:9783642309649 751: 747: 746: 738: 734: 724: 721: 720: 707: 700: 696: 693: 689: 684: 673: 666: 662: 659: 655: 650: 639: 634:Quasiregular 633: 632: 626: 624: 619: 617: 613: 609: 605: 601: 596: 594: 590: 586: 576: 573: 570: 567: 564: 561: 556: 552: 549: 542: 535: 528: 514:Star polygon 513: 510: 507: 504: 503: 497: 493: 490: 486: 483: 479: 478: 477: 475: 471: 467: 446: 442: 433: 429: 420: 416: 412: 409: 396: 392: 391: 390: 388: 378: 376: 371: 363: 361: 357: 353: 349: 348: 343: 339: 338: 333: 329: 324: 322: 318: 314: 310: 306: 298: 293: 282: 277: 275: 270: 268: 263: 262: 260: 259: 253: 250: 248: 245: 243: 240: 238: 235: 233: 230: 228: 225: 223: 220: 218: 215: 214: 212: 211: 207: 206: 203: 202:Star polygons 200: 199: 191: 189: 185: 182: 178: 174: 170: 166: 163: 159: 155: 152: 148: 144: 136: 133: 131: 127: 79: 77: 73: 67: 65: 61: 57: 55: 51: 47: 44: 41: 37: 30: 25: 20: 1346: 1252:>20 sides 1187:Decagon (10) 1172:Heptagon (7) 1162:Pentagon (5) 1152:Triangle (3) 1047:Equidiagonal 915: 854: 850: 840: 828: 823: 815: 810: 801: 787: 780: 775:, on Perseus 772: 764: 744: 737: 653:t{5} = {10} 640:Quasiregular 620: 597: 582: 474:star polygon 463: 405: 384: 381:Applications 372: 369: 359: 355: 351: 345: 335: 327: 325: 313:star polygon 308: 302: 241: 188:Dual polygon 1479:10 (number) 1448:Star-shaped 1423:Rectilinear 1393:Equilateral 1388:Equiangular 1352:Hendecagram 1196:11–20 sides 1177:Octagon (8) 1167:Hexagon (6) 1142:Monogon (1) 984:Equilateral 387:girih tiles 340:, with the 330:combines a 323:is {10/3}. 247:hendecagram 173:equilateral 1473:Categories 1453:Tangential 1357:Dodecagram 1135:1–10 sides 1126:By number 1107:Tangential 1087:Right kite 729:References 517:Compounds 489:pentagrams 252:dodecagram 161:Properties 1433:Reinhardt 1342:Enneagram 1332:Heptagram 1322:Pentagram 1289:65537-gon 1147:Digon (2) 1117:Trapezoid 1082:Rectangle 1032:Bicentric 994:Isosceles 971:Triangles 907:202575183 883:0080-4614 637:Isogonal 511:Compound 496:pentagons 326:The name 237:enneagram 227:heptagram 217:pentagram 1408:Isotoxal 1403:Isogonal 1347:Decagram 1337:Octagram 1327:Hexagram 1128:of sides 1057:Harmonic 958:Polygons 717:See also 610:and the 466:polygram 328:decagram 309:decagram 305:geometry 242:decagram 232:octagram 222:hexagram 181:isotoxal 177:isogonal 135:Dihedral 54:vertices 1428:Regular 1373:Concave 1366:Classes 1274:257-gon 1097:Rhombus 1037:Crossed 899:0062446 863:Bibcode 861:: 411. 857:(916). 818:p.36-38 587:and 4D 571:{10/3} 562:Symbol 508:Convex 470:decagon 360:grammēs 356:ÎłÏÎ±ÎŒÎŒáż†Ï‚ 344:suffix 151:degrees 1438:Simple 1383:Cyclic 1378:Convex 1102:Square 1042:Cyclic 1004:Obtuse 999:Kepler 905:  897:  889:  881:  769:ÎłÏÎ±ÎŒÎŒÎź 752:  522:Image 491:2{5/2} 482:digons 449:{(5/4) 436:{(5/3) 423:{(5/2) 350:. The 169:cyclic 70:t{5/3} 68:{10/3} 1413:Magic 1009:Right 989:Ideal 979:Acute 903:S2CID 891:91532 887:JSTOR 792:(PDF) 505:Form 498:2{5}. 352:-gram 347:-gram 342:Greek 337:deca- 50:Edges 1443:Skew 1067:Kite 962:List 879:ISSN 750:ISBN 484:5{2} 307:, a 192:self 165:star 52:and 39:Type 871:doi 855:246 602:or 406:An 303:In 156:72° 1475:: 901:. 895:MR 893:. 885:. 877:. 869:. 853:. 831:, 618:. 453:} 440:} 427:} 389:. 334:, 179:, 175:, 171:, 167:, 139:10 137:(D 58:10 964:) 960:( 950:e 943:t 936:v 909:. 873:: 865:: 844:* 835:. 796:. 759:. 451:α 438:α 425:α 358:( 280:e 273:t 266:v 153:) 149:( 141:)

Index


Regular star polygon
Edges
vertices
SchlÀfli symbol
Coxeter–Dynkin diagrams
Symmetry group
Dihedral
Internal angle
degrees
star
cyclic
equilateral
isogonal
isotoxal
Dual polygon
Star polygons
pentagram
hexagram
heptagram
octagram
enneagram
decagram
hendecagram
dodecagram
v
t
e

Islamic geometric patterns

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