Question

∠A=5x−15 ∘ start color #11accd, angle, A, end color #11accd, equals, start color #11accd, 5, x, minus, 15, degrees, end color #11accd ∠ B = 2 x + 2 1 ∘ ∠B=2x+21 ∘

Answer 1

Answer: 45°

Explanation:

Given that :

∠A=5x−15°---(1)

∠B=2x+21°----(2)

Equating

∠A = ∠B

(5x−15)° = (2x+21)°

5x - 15 = 2x + 21

Collecting like terms

5x - 2x = 21 + 15

3x = 36

x = 12

Substitute x = 12 in either angle A or B since both are congruent

∠A=(5x−15)°

∠A = (5(12) - 15)°

∠A = (60 - 15)°

∠A = 45°

∠A = ∠B = 45°