Answer:
n = number of sides
The measure of each interior angle of a regular polygon is 180(n -2) .
we know that the sum of the interior angles is 540°
to find the number of sides:
540°= 180°(n-2)
540°=180n-360°
540+360 = 180n
900=180n
n = 900/180 = 5
the polygon has 5 sides (pentagon)