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HELP Find the number of non-degenerate triangles whose vertices are three of the points on this six-point star.

HELP Find the number of nondegenerate triangles whose vertices are three of the points on this sixpoint star class=

Respuesta :

sqdancefan

Answer:

20

Step-by-step explanation:

The number of combinations of 6 points taken 3 at a time is ...

6!/(3!·(6-3)!) = 6·5·4/(3·2·1) = 5·4 = 20

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If you number the points 1–6, the points of the 20 triangles will be ...

123 124 125 126 134

135 136 145 146 156

234 235 236 245 246

256 345 346 356 456

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