Identify the side lengths of the triangle. I don't get this question at all. PLEASE HELP!!

The triangle tells us that 8x - 4 is equal to 4x + 16 we set them equal to eachother 8x - 4 = 4x + 16 and solve for x
8x - 4x - 4 = 16
4x + 4 - 4 = 16 + 4
4x = 20
x = 5
Then you plug the x value in for x on all 3 of the problems.
8(5) - 4 = 36
4(5) + 16 = 36
5(5) + 7 = 32
Therefore, the correct answer should be B