Answer:
∠ c = 120°
Explanation:
the sum of the interior angles of a polygon is
sum = 180° (n - 2) ← n is the number of sides
here n = 6 , then
sum = 180° × 4 = 720°
since the hexagon is regular then the interior angles are congruent , so
∠ c = 720° ÷ 6 = 120°