The volume of any prism is the product of the base area and the height of the prism. Here, we can take the "base" to be the front face of the assembly, and its "height" to be the 3 cm distance between the front and back faces.
The front face area is the sum of the triangle area and the rectangle area.
A = 1/2bh + LW
A = (1/2)(10 cm)(4 cm) + (16 cm)(2 cm) = 52 cm²
Then the volume is ...
V = Bh = (52 cm²)(3 cm) = 156 cm³ . . . . total volume of the two blocks
