# Math Help - isosceles triangle

1. ## isosceles triangle

In the isosceles triangles ABC and CDE below, BC = 16 in., DE = 11 in. What is CD - AD?

Here

2. Hello, sanee66!

In the isosceles triangles $ABC$ and $CDE$ below,
. . $BC = 16\text{ in.},\;DE = 11\text{ in.}$
What is $CD - AD$?
Code:
            A
*
*   *  D       11
*       *   *   *   *   * E
*           *           *
*               *       *
*                   *   *
B *   *   *   *   *   *   * C
16
We have: . $AC \:=\:BC\:=\:16$
. . . .and: . $DC \:=\:DE\:=\:11$

Hence: . $AD \;=\;AC - DC \;=\;16 - 11\;=\;5$

Therefore: . $CD - AD\;=\;11 - 5 \;=\;6$