2005 AMC 8 Problems/Problem 21
Contents
Problem
How many distinct triangles can be drawn using three of the dots below as vertices?
Solution
The number of ways to choose three points to make a triangle is . However, two* of these are a straight line so we subtract
to get
.
- Note: We are assuming that there are no degenerate triangles in this problem, and that is why we subtract two.
Video solution
https://www.youtube.com/watch?v=XQS-KVW1O6M
See Also
2005 AMC 8 (Problems • Answer Key • Resources) | ||
Preceded by Problem 20 |
Followed by Problem 22 | |
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All AJHSME/AMC 8 Problems and Solutions |
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.