What rectangles can be with a perimeter of 20 units?

Rectangles with a perimeter of 20 units can have various dimensions, as long as the sum of the lengths of all four sides equals 20 units. One example could be a rectangle with sides measuring 4 units by 6 units, as 4 + 4 + 6 + 6 = 20. Another example could be a square with sides measuring 5 units each, as 5 + 5 + 5 + 5 = 20. In general, rectangles with sides of any length that add up to 20 units can have a perimeter of 20 units.