1989 AIME Problems/Problem 2
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Problem
Ten points are marked on a circle. How many distinct convex polygons of three or more sides can be drawn using some (or all) of the ten points as vertices?
Solution
Any subset of the ten points with three or more members can be made into exactly one such polygon. Thus, we need to count the number of such subsets. There are 
total subsets of a ten-member set, but of these 
have 0 members, 
have 1 member and 
have 2 members. Thus the answer is 
.
See also
| 1989 AIME (Problems • Resources) | ||
| Preceded by Problem 1 | Followed by Problem 3 | |
| 1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 | ||
