Do we need to think about area and perimeter in each case?

Yss,I think we need to think about area and perimeter in each case because the area and perimeter of any geometric shapes determines the cost of flooring, Length breadth ,height, volume, etc.

whatever you can spend with $11.53 or under.

step-by-step explanation:

20 - 8.47 = 11.53. take away the money he used for lunch from the starting amount of 20.