Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 1 - No. 14)
In a triangle, if a = 8 cm, b = 10 cm, and angle A = 40°, find the measure of angle B (approximately):
40°
51.3°
60°
75°
Explicació
Using the sine rule: sinB / b = sinA / a. sinB = (b * sinA) / a = (10 * sin40) / 8. B ≈ 51.3°.