Answer:
8
Explanation:
Measure of one interior angle of a regular polygon of n sides:
(n - 2)180/n
Measure of one exterior angle of a regular polygon if n sides:
360/n
"the interior angle is thrice the exterior angle"
(n - 2)180/n = 3 * 360/n
(n - 2)180 = 3 * 360
n - 2 = 3 * 2
n = 8
The number of sides is 8.