Question

Marita is decorating the prism at the right with tiles. Each tile is 1 square foot. Each tile costs $ 0.45. How much will it cost Marita to tile the whole prism?

Answer 1

First, we need to calculate the surface area of the prism, to know how much space we need to cover. An important fact to keep in mind is that with a cuboid, there are three pairs of identical faces. This means that there are:
Two faces with a surface area of 2×1=2ft²
Two faces with a surface area of 3×2=6ft²
and two faces with a surface area of 1×3=3ft²
So, the total surface area of the shape is:
2(2)+2(6)=2(3)
=4+12+6
=22ft²
Knowing that each tile costs 1ft², then Marita will need 22÷1=22 tiles. Therefore, the total cost of tiling the whole prism is 22×0.45= $9.90