Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 2 - No. 30)
In a right triangle ABC, angle B is 90 degrees, and angle A is 30 degrees. If side AB is 5 cm, what is the length of side BC?
2.5 cm
5 cm
8.66 cm
10 cm
คำอธิบาย
BC/AB = tan(30), BC = AB * tan(30), BC = 5cm * (1/√3) ≈ 2.5 cm