What is the surface area of a rectangular prism with the length of 20, a height of 18, and a width of 5?
Surface area =
2 [ lw + lh + hw ] =
2 [ 20*5 + 20*18 + 18*5] =
2 [ 100 + 360 + 90] =
2 [ 550] =
1100 sq units
