The area of your rectangle will vary depending on the dimensions. The area of any rectangle can be found with a simple equation...
Area = Length x Width or A = l x w
The answer to the area question will ALWAYS be in square units because when you multiply, you also multiply the units so, for example 2 inches x 2 inches = 4 inches^2.
Let's take a look at an example... You have a rectangle with a length of 8 feet and a width of 4 feet. What's the area?
Well... Area = Length x Width, so
Area = 8 ft x 4 ft
Area = 32 ft^2
Easy as that!