Posted by **Ella** on Wednesday, April 21, 2010 at 10:47am.

A.

A parallelogram has a 7-inch side and a 9-inch side, and the longer diagonal is 14 inches long. Find the length of the other diagonal. Do you need your calculator to do it?

B. (Continuation) Evaluate 72 + 92 + 72 + 92 − 142 − d2, where d is the length of the

shorter diagonal. Hmm. . .where have you seen this before?