"in quadrilateral qrst, m∠q is 68°, m∠r is (3x + 40)°, and m∠t is (5x − 52)°. what are the measures of ∠r , ∠s , and ∠t ? write the numerical values in that order with the measures separated by commas. "

TQRS is an inscribed quadrilateral.
5 x - 52° + 3 x + 40° = 180°
8 x - 12° = 180°
8 x = 180° + 12°
8 x = 192°
x = 192° : 8 = 24°
m∠ R = 3 · 24° + 40° = 112°
m∠ T = 5 · 24° - 52° = 68°
m∠ S = 360° - ( 68° + 68° + 112° ) = 112°
 
m∠R, m∠S, m∠T = 112°, 112°, 68°.