The surface area of the two triangles is 12 cm^2.
3*4=12
The surface area of the bottom rectangle is 8 cm^2.
4*2=8
The surface area of the rectangle that is on the left side of the figure is 6 cm^2.
3*2=6
The surface area of the rectangle that is on the top side of the figure is 10 cm^2.
To find the third side of the triangle, use the Pythagorean theorem.
3^2+4^2=h^2
9+16=25
The third side of the triangle is 5 cm.
The surface area of the whole figure is 36 cm^2.
12+8+6+10=36