Question

What is the value of x in the figure below?

Answer 1

Option D.
`x=45/4\ units`

Explanation:

we know that

In the right triangle ABC

The function cosine of angle C is equal to divide the adjacent side to the angle C (AC) by the hypotenuse (BC)

substitute the values

cos(C)=15/20 ----> equation A

In the right triangle CAD

The function cosine of angle C is equal to divide the adjacent side to the angle C (CD) by the hypotenuse (AC)

substitute the values

cos(C)=x/15 -----> equation B

equate equation A and equation B

`15/20=x/15\\ \\x=15^(2) /20\\ \\x=225/20\ units`

Simplify

Divide by 5 both numerator and denominator

`x=225/20=45/4\ units`