Rhombus inscribed in a rectangle

[KatieK]

I can't figure this one out.

In rectangle ABDE, AB=12 and BD=16. For rhombus ACDF, find the difference between the are and the perimter.

 

[Ishuda]

I can't figure this one out.

In rectangle ABDE, AB=12 and BD=16. For rhombus ACDF, find the difference between the are and the perimter.

What are your thoughts? What have you done so far? Please show us your work even if you feel that it is wrong so we may try to help you. You might also read
http://www.freemathhelp.com/forum/threads/78006-Read-Before-Posting

Hint: Given no more information than that, the question does not have a unique answer.