How many triangles are in a 5 point circle?

Answer 1

This question is hard to answer because the poster isn't clear on what a "5 point circle" is. I'll answer one possibility, and then if I interpreted it wrong, the poster can come back and clarify.

Suppose you pick five points on the circumference of a circle and connect them all up with straight lines. You'll create a spiderweb of lines that has lots of triangles in it. How many triangles are there, exactly?

Since some of the triangles overlap and cross others, it's a little hard to know what to count. If you count all triangular regions, whether or not they overlap other triangles, you get thirty.

Please let me know if any of my assumptions was wrong.