Question

Find the value of x. If necessary, round your answer to the nearest tenth. The figure is not drawn to scale.
AB = 19, BC = 10, and CD = 5

Answer 1

CB*CA=CD*(CD+x)

Answer 2

?

Answer 3

The intersecting secant theorem. Two secant lines that meet at a point have lengths that are equal from that point. So from point C, the length of CB*CA or CB*(CB+BA) is equal to CD*(CD+x), so you just solve for x.