SAT math practice question: Right triangles and lengths

 
Try the following SAT math practice question (Calculator permitted) that tests your understanding of using the properties of right triangle to find the length of line segments.

In right triangle $ABC$ shown below, what is the length of line segment $DE$ ?

1. $\quad 6.9$
2. $\quad 7.2$
3. $\quad 7.5$
4. $\quad 8$