Alandscaper has 125 tiles to build a square patio. the patio must have an area of at least 80 square square feet. what are the possible arrangments for the patio?

Given that a square patio of at least 80 square feet is to be built from 125 tiles of length 12 inches or 1 feet.

Part A;
Since there are 125 tiles and the patio has a shape of a square of at least 80 square feet, then the possible dimensions of the patio are

9 ft by 9 ft = 81 ft
10 ft by 10 ft = 100 ft, and
11 ft by 11 ft = 121 ft.

Part B.
For a patio of dimensions, 9ft by 9ft, the number of tiles that will not be used is given by 125 - 81 = 44

For a patio of dimensions, 10ft by 10ft, the number of tiles that will not be used is given by 125 - 100 = 25

For a patio of dimensions, 11ft by 11ft, the number of tiles that will not be used is given by 125 - 121 = 4

The answer would be 24mm