To find the area of a rectangle, you multiply its length by its width. In this case, to calculate the area of a rectangle that is 30 feet long and 20 feet wide, you would multiply those two dimensions:
Area = Length × Width Area = 30 ft × 20 ft Area = 600 square feet
Therefore, the area of a rectangle that is 30 feet long by 20 feet wide is 600 square feet.