It is 255 cm^2
This is a very basic area problem. You should try refreshing on some of your multiplication and addition skills. Try reading patterns, maybe. Also learning geometric proofs is VITAL.
Check the picture below, notice those three quadrilaterals.
the square, is really a rectangle and is also a rhombus, but with right-angles and equal sides.
13-(3/2x)=37
3/2x=24
1.5x=24
x=16