I'll try my best on this:
We can split this into two rectangles from the vertical 5cm line, up to the long 13 cm line.
After cutting this, we now have two rectangles:
A rectangle with length 5 + 2 = 7 cm, and width 5 cm, and another rectangle with width 13 - 5 = 8cm, and length 2 cm.
Area for 7 x 5 rectangle:
7 * 5 = 35.
Area for 8 x 2 rectangle:
8 * 2 = 16.
Add:
35 + 16 = 51
