Answer:
62 square units
Step-by-step explanation:
The area of a rectangular prism is the sum of the areas of its six faces. Opposite faces have the same area, so it is the sum of 3 pairs of faces. The area of one face of each pair is the product of the dimensions of that face. Those three areas are ...
• L·W
• W·H
• H·L
so the total surface area is ...
A = 2(LW +WH +HL)
For hand calculation, this can be simplified a bit to ...
A = 2(LW +H(L+W)) . . . . . requires one less multiplication
For your prism, the area is ...
A = 2(5·2 + 3(5+2)) = 2(10 +21) = 62 . . . square units
