Question

15 points are placed on a circle. How many triangles is it possible to form, such that their vertices will be the given points?

Answer 1

455

Explanation:

There are 15 points on a circle.

We need three points to form a triangle

Therefore the number of triangles = 15 choose 3 ​= 15!/(3!x12!)​ = (15x14x13)/(3x2x1) = 5x7x13 = 455

Hence the number of triangles formed is 455

Answer 2

Answer: 445 triangles can be form with 15 dots of a circle (I hope good luck)

Explanation: