Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 4 - No. 10)

If sinA = 0.6 and angle A is obtuse, what is the value of angle A?

36.87°

53.13°

126.87°

143.13°

Use arcsin(0.6) = 36.87, then find the supplementary angle of 36.87° by subtracting it from 180° (180 - 36.87 = 143.13).