Question

Helllppp plzzz.....​

Answer 1

BC ≈ 19.4 cm

Explanation:

Using the cosine ratio in the right triangle

cos71° =
`(adjacent)/(hypotenuse)` =
`(AB)/(BC)` =
`(6.3)/(BC)` ( multiply both sides by BC )

BC × cos71° = 6.3 ( divide both sides by cos71° )

BC =
`(6.3)/(cos71)` ≈ 19.4 cm ( to 3 significant figures )

Answer 2

BC= 19.4 (3s.f.)

Explanation:

Since Angle CAB = 90

Therefore Angle ACB = 180° - 90° -71° = 19°

Using Sine Rule,

6.3cm/Sin(19°) = BC/Sin(90°)

BC= 19.350787697

= 19.4 cm (3 S.F.)