Question

Someone help please!

Answer 1

Answer:

BC ≈ 14.7 m

Step-by-step explanation:

Using the Sine rule in Δ ABC

$\frac{AB}{sinC}$ = $\frac{BC}{sinA}$

To find ∠ A subtract the 2 given angles from 180°

∠ A = 180° - (90 + 28)° = 180° - 118° = 62°

Then

$\frac{7.8}{sin28}$ = $\frac{BC}{sin62}$ ( cross- multiply )

BC × sin28° = 7.8 × sin62° ( divide both sides by sin28° )

BC = $\frac{7.8sin62}{sin28}$ ≈ 14.7 m ( to 3 significant figures )