Answer:
A decagon has 10 sides so its interior angles add up to 180(10) - 360 = 1440 degrees. Therefore, on average, each interior angle is 144 degrees and each exterior angle is 36 degrees. The sum of the exterior angles is 10 x 36 = 360 degrees.
Explanation:
The total sum of the interior angles of a simple decagon is 1440°