Answer:
x = 70 , ∠ A = 140° , ∠ B = 130°
Explanation:
the sum of the interior angles of a polygon is calculated as
sum = 180° (n - 2) ← n is the number of sides
here n = 5 , then
sum = 180° × (5 - 2) = 180° × 3 = 540°
sum the 5 angles, equate to 540 and solve for x
2x + 2x - 10 + 90 + 90 + 90 = 540 ( simplify left side )
4x + 260 = 540 ( subtract 260 from both sides )
4x = 280 ( divide both sides by 4 )
x = 70
Then
∠ A = 2x = 2 × 70 = 140°
∠ B = 2x - 10 = 2(70) - 10 = 140 - 10 = 130°