Answer:
Explanation:
Because midpoints were used to make similar triangles we can say
AC=2(DE)
5x+12=2(9x-20)
5x+12=18x-40
-13x+12=-40
-13x=-52
x=4
AC=5x+12
AC=5(4)+12
AC=20+12
AC=32
DE = (1/2) * AC {Midpoint theorem}
2(9x - 20) = 5x + 12
2*9x - 2*20 = 5x + 12
18x - 40 = 5x + 12
18x -5x - 40 = 12
13x - 40 = 12
13x = 12+40
13x = 52
x = 52/13
x = 4
AC = 5x + 12
= 5*4 + 12
= 20 +12
AC = 32
6.5m questions
8.6m answers