Answer:
5
Step-by-step explanation:
First, notice that these two triangles are similar using AA.
Because sides BC and EC are corresponding, you can divide 24 by 8, to determine that the ratio of similitude is 3.
That means that because sides AC and DC are corresponding, 25 - 2x divided by x is 3.
25 - 2x / x = 3
25 - 2x = 3x
25 = 5x
x = 5
x is the same as side CD, so CD = 5.
