m∠Q + m∠S = 180 ⇒ 68 + m∠S = 180
m∠S = 112
m∠R + m∠T = 180 ⇒ (3x + 40) + (5x - 52) = 180
8x - 12 = 180
8x = 192
x = 24
m∠R = 3(24) + 40 = 112
m∠T = 5(24) - 52 = 68
∠R = 112, ∠S = 112, ∠T = 68