Question

12. What is the sum of the interior angles for a pentagon? (1 point)

900
540°
720°
108°

Answer 1

540°

Explanation:

Consider a regular pentagon. Divide it radially into five congruent, isosceles triangles. Each triangle has a vertex angle of 360°/5 = 72°, and base angles of (180°-72°)/2 = 54° each.

An interior angle of the pentagon is made up of two of those 54° angles, so interior angle = 108°.

Sum of interior angles = 5·108° = 540°