Question

10 POINTS!! HELP ASAP!! What is the length of AC?

Answer 1

D. 144

Explanation:

Triangle BAC is similar to triangle DEC, so you can set up a ratio:

`(84)/(156-x) = (7)/(x)`

Then cross multiply

84x = 7 (156 - x)

84x = 1092 - 7x

Add 7x to both sides.

91x = 1092

Divide both sides by 91.

x = 12

AC = 156 - x

AC = 156 - 12

AC = 144

Answer 2

D

Explanation:

Δ CED and Δ CAB are similar thus the ratios of corresponding sides are equal, that is

`(CE)/(CA)` =
`(ED)/(AB)` , substitute values

`(x)/(156-x)` =
`(7)/(84)` =
`(1)/(12)` ( cross- multiply )

12x = 156 - x ( add x to both sides )

13x = 156 ( divide both sides by 13 )

x = 12

Thus

AC = 156 - x = 156 - 12 = 144 → D