Question

Find the length of side BC.
Give your answer to 3 significant figures

Answer 1

`\huge\boxed{\sf BC = 19.4 \ cm}`

Explanation:

Given:

θ = 71°

Adjacent = AB = 6.3 cm

Required:

Hypotenuse = BC = ?

We will use the trigonometric ratio of cos.

`\displaystyle cos \theta = (Adjacent)/(Hypotenuse) \\\\cos \ 71 = (6.3)/(BC) \\\\0.33 = (6.3)/(BC) \\\\BC =(6.3)/(0.33) \\\\\boxed{BC = 19.4 \ cm}\\\\\rule[225]{225}{2}`