Question 658207
The area of one side is:

A = l * w
For a square, A = s^2 since the sides are equal.

A=2.1 ft * 2.1 ft 
A= 4.41 ft^2

Since there are 6 sides on the cube, the surface area is 6 times the area of one side.

SA = 6 * 4.41 ft^2 = 26.46 ft^2