If the exterior angle of a regular polygon is 45°, how many diagonals does the polygon have?
Show answer & explanation
Correct answer: A
Explanation
Exterior angle = 45°
n = 360 / exterior angle
Diagonal = n(n − 3) / 2
n = 360 / 45 = 8
Diagonal = 8(8 − 3) / 2
= 8 × 5 / 2
= 40 / 2
= 20