Take into account that the surface area of a figure, is the area of the faces of the figure, excepting the top and the bottom.
Then, for the given figure, you have:
lateral surface area = (5 cm)(1 cm) + (5 cm)(1 cm) + (10 cm)(1 cm) + (10 cm)(1 cm)
= 30 cm²
Hence, the lateral surface area is 30 cm²
