What is required in this is to find the area of each piece.
First rectangle (top)
A=13*4
A=52
Second rectangle (bottom)
A=12*4
A=48
Third rectangle (left side)
A=5*4
A=20
Triangles (both (causing us to multiple by 2 in the problem) because they have the same length and width)
A=1/2*5*12*2
A=5*12 (1/2 and 2 cancel out)
A=60
Now add them up:
52+48+20+60=SA (remember 60 is both triangles so we only have 4 measurements)
180=SA