Question

What is the length of AC

Answer 1

|AC| = 144

Explanation:

The larger triangle (on the left) and the smaller one (on the right) are similar.

Therefore the following equation of ratios is correct:

x 7

---------- = ---------

156 - x 84

Then 84x = 7(156) - 7x, or

91x = 1092, or x = 12

Then the length of AC is 156 - x, or 144

Answer 2

k = 84/7 = 12
(156 - x)/12 = x
12x = 156 - x
13x = 156
x = 12

AC = 156 - 12
AC = 144