Question

what is the number of sides of a regular polygon having the given angle sum 3240​

Answer 1

Answer:

(n-2)×180=3240

after solving this equation we get

n=20

Answer 2

Answer:

Obviously, 3240 deg is the sum in the interior angles of a regular polygon (of n sides).

Now (n-2)*180 = 3240, or

n-2 = 18, or

n = 20 sides.

Check: Each exterior angle of the 20-sided polygon = 360/20 = 18 deg. Then each interior angle = 180–18 = 162 deg. Sum of the 20 interior angles = 20*162 = 3240 deg. Correct.