Question

In the right triangle below, use special right triangle ratios to find the exact length of BC.

A. 15 cm

B. 10√3cm

C. 15√2cm

D. 15√3cm

Answer 1

Answer:

The answer is D.

Step-by-step explanation:

In order to find BC, you have to use Cosine Rule, cosθ = adjacent/hypotenuse. So you have to substitute the values into the formula :

$\cos(θ) = \frac{adj.}{hypo.}$

Let adj. = BC,

Let hypo =30cm,

Let θ = 30°,

$\cos(30) = \frac{bc}{30}$

$bc = 30 \cos(30)$

$bc = 15 \sqrt{3} cm$