Difference between revisions of "2013 AMC 10A Problems/Problem 25"
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| − | + | All 20 diagonals are drawn in a regular octagon. At how many distinct points in the interior | |
| + | of the octagon (not on the boundary) do two or more diagonals intersect? | ||
| − | + | <math> \textbf{(A)}\ 49\qquad\textbf{(B)}\ 65\qquad\textbf{(C)}\ 70\qquad\textbf{(D)}\ 96\qquad\textbf{(E)}\ 128 </math> | |
| − | |||
| − | (A) 49 | ||
| − | (B) 65 | ||
| − | (C) 70 | ||
| − | (D) 96 | ||
| − | (E) 128 | ||
| + | ==Solution== | ||
70-5-16=49, so THE ANSWER IS A | 70-5-16=49, so THE ANSWER IS A | ||
Revision as of 23:10, 6 February 2013
All 20 diagonals are drawn in a regular octagon. At how many distinct points in the interior of the octagon (not on the boundary) do two or more diagonals intersect?
Solution
70-5-16=49, so THE ANSWER IS A
