area of rectangle ( bottom)
12x4=48
side of rectangle ( 2 of them)
4x3x2=24
length of rectangle (2 of them)
12x3x2=72
area of triangle facing us ( 2 of them)
1/2x5x12x2= 60
top part of triangle
13x4= 52
back part of triangle :
4x5=20
total = add them all together
= 276