Question

What is the length of AC ?

3ft
4ft
9ft
18ft

Answer 1

The answer is D, 18ft.

Explanation:

The length of AC is 18 ft.

Answer 2

ΔACB and ΔMNB are similar. Therefore the corresponding sides are in proportion:

`(AC)/(MN)=(CB)/(NB)\\\\MN=9\ ft\\CB=2\cdot3\ ft=6\ ft\\NB=3\ ft`

Substitute:

`(AC)/(9)=(6)/(3)\\\\(AC)/(9)=2\ \ \ \ |\cdot9\\\\AC=18\ ft`