Answer:
9
Explanation:
interior angle + exterior angle = 180°, that is
7y + 2y = 180
9y = 180 ( divide both sides by 9 )
y = 20
Then
2y = 2 × 20 = 40°
The sum of the exterior angles of a polygon = 360°
Divide the sum by 40 for number of sides (n)
n =
= 9