One of the angles of a regular decagon is 144°. What is the sum of the measures of all the interior angles of this decagon? A. 792°

B. 1056°

C. 1440°

D. 1584°

Answer: 1440

Step-by-step explanation:

Regular means all angles are equivalent. Since their are 10 sides in the decagon, the sum of the interior angles is 144 * 10.

Alternatively, the sum of the measures of the interior angles in the decagon, can also be found by applying the formula (n-2) * 180, where n is the number of sides.

The answer would be c. 1440

Decagon has 10 sides. And one angle is 144. So you would multiply it by 10 and the sum of all the angles would be 1440.