The size of each interior angle of a regular polygon is 8 times the size of

each exterior angle.

Work out how many sides the polygon has.

Let the size of each exterior angle be x degrees in your working.

the polygon has 18 sides

Step-by-step explanation:

Exterior angle = x Interior angle = 180 - x

180 - x = 8x

9x = 180

x = 20

interior angle = 180 - 20 = 160

side of polygon = n

160n = 180 (n - 2)

160n = 180n - 360

20n = 360

n = 18