Question

A polygon is such that when all diagonals from one vertex are drawn, eleven triangles are formed. How many sides does the polygon have?

9
11
12
13

Answer 1

13. There are 13 sides to this polygon. 

Answer 2

Option D, 13

Explanation:

A polygon is such that when all diagonals from on vertex are drawn, eleven triangles are formed.

We have to tell number of sides of the polygon.

Since number of triangle"y" formed by "n" number of vertices can be represented by (n-2) = y

By putting y = 11 in the equation

11 = (n-2)

n = 13

Option D is the answer.