**Magoosh**

If a rectangle has perimeter of 20 and a diagonal with length 9, what is the area of the rectangle?

A. 7.5

B. 8

C. 8.5

D. 9

E. 9.5

OA E

Perimeter is 20

So, 2(l+b)=20

i.e l+b=10

Squaring both sides,

\(^{l^2}\) + \(^{b^2}\) + 2lb = 100

Also, diagonal is 9,

So, \(^{l^2}\) + \(^{b^2}\) = \(^{9^2}\)

Or \(^{l^2}\) + \(^{b^2}\) = 81

Subtracting 2nd equation from 1st,

we get 2lb = 19

or lb = 9.5

Area = lb = 9.5

Option E.