Assuming length and width are whole numbers, a rectangle with an area of 64 units can be constructed in four different ways: 8 x 8, 4 x 16, 2 x 32 or 1 x 64. A square is a special case of a rectangle, as it has equal sides.
If the length and width of the rectangle can be any values, the number of possible rectangles with areas of 64 units is virtually infinite. For example, a rectangle with the dimensions 2.5 x 25.6 has an area of 64, as does one with the dimensions 10.24 x 6.25. In fact, any two rational numbers that have a product of 64 can be the length and width of a rectangle with an area of 64 units.