Question

How many diagonals are there in a polygon having 20 sides.

Answer 1

Answer:

170. is the right answer

Answer 2

Step-by-step explanation:

Given:-

20 sided polygon

To find:-

How many diagonals are there in a polygon having 20 sides. ?

Solution:-

Given that

Number of sides in the given polygon = 20

n = 20

We know that

Number of diagonlos in a polygon whose sides are n is n(n-3)/2

On substituting the value of n in the above formula then

=> Number of diagonals

=> 20(20-3)/2

=> 20×17/2

=> 340/2

=> 170

Number of diagonals = 170

Answer:-

The number of diagonals of a polygon of 20 sides is 170

Used formula:-

Number of diagonlos in a polygon whose sides are n is n(n-3)/2