Hello, stones44!

We will need Trignometry for this one . . . the Law of Cosines.

One side of the parallelogram is 7, the other is 9.

The long diagonal is 14.

What is the short diagonal?We have parallelogram with:Code:A 9 B * - - - - - - - - * / * / / * / 7/ * / 7 / * 14 / / * / * - - - - - - - - * D 9 C

. . and we want the length of diagonal

First, find

. . In

Then

In

Therefore: .