Question

Find BC in angle ABC
Round to the nearest tenth.

BC=?

Answer 1

BC ≈ 18.7

Explanation:

using the sine rule in Δ ABC

`(BC)/(sinA)` =
`(AC)/(sinB)` ( substitute values )

`(BC)/(sin67)` =
`(20)/(sin80)` ( cross- multiply )

BC × sin80° = 20 × sin67° ( divide both sides by sin80° )

BC =
`(20sin67)/(sin80)` ≈ 18.7 ( to the nearest tenth )