Example:
The total surface area of a cube is 4056 square metres. Find the length of its edge.

Solution:
Let the edge of the cube be l metres, Then we have the total surface area = 6l^{2}
But we have given that the total surface area = 4056 square metres.
\ 6l^{2} = 4056
Þ l^{2} = 4056/6
Þ l^{2} = 676
Taking square roots on both sides, we get
Öl^{2} = Ö676
\ l = 26
\ The length of the edge of the cube = 26 metres.

Directions: Solve the following problems. Also write at least ten examples of your own.