Question

Find the length of BC. Round your answer to two decimal places.

Answer 1

$\\ \rm\Rrightarrow cos40=\dfrac{Base}{Hypotenuse}$

$\\ \rm\Rrightarrow cos40=\dfrac{a}{10}$

$\\ \rm\Rrightarrow 0.766=a/10$

$\\ \rm\Rrightarrow a=0.766(10)$

$\\ \rm\Rrightarrow a=76.6$

Answer 2

Answer:

7.66 (dp)

Step-by-step explanation:

Use the cosine trig ratio:

$\mathsf{\cos(\theta)=\dfrac{A}{H}}$

where:

• $\theta$ is the angle
• A is the side adjacent the angle
• H is the hypotenuse

Given:

• $\theta$ = 40°
• A = a
• H = 10 in

Substituting the given values into the equation:

$\implies \mathsf{\cos(40)=\dfrac{a}{10}}$

$\implies \mathsf{a=10\cos(40)}$

$\implies \mathsf{a=7.660444431...}$

$\implies \mathsf{a=7.66 \ (2 \ dp)}$