### Home > CC4 > Chapter 11 > Lesson 11.1.1 > Problem 11-7

11-7.

In the diagram at right, Δ *ABC*and Δ*ADE*are similar. If*AB*= 5,*BD*= 4, and*BC*= 7, what is*DE*? Homework Help ✎

Separate the triangles into two similar triangles.

What is the length of *AD*? Once you know this, since the triangles are similar, the ratios of corresponding sides are equal.

Remember to set up proportions.

*DE* = 12.6