David parked his rectangular car in an empty rectangular parking lot. The dimensions of the parking lot are 87 feet by 83 feet, and the dimensions of the car are 18 feet by eight feet. What area of the parking lot is still empty?
In order to calculate the area of the parking lot that is empty, we need to subtract the area of the car from the area of the whole parking lot. The area of any rectangle can be calculated by multiplying the length by the width. The area of the parking lot is therefore equal to 87 feet multiplied by 83 feet. One way of calculating this would be using the grids or box method. 80 multiplied by 80 is 6400. 80 multiplied by seven is 560. 80 multiplied by three is 240. And finally, seven multiplied by three is 21. Adding these four numbers gives us 7221. As the dimensions are in feet, the area of the parking lot is 7221 square feet.
We can calculate the area of the car by multiplying 18 by eight. This is equal to 144. 10 multiplied by eight is 80, and eight multiplied by eight is 64. The area taken up by the car is 144 square feet. Subtracting this from 7221 will give us the empty area. This is equal to 7077. So the area of the parking lot that is still empty is 7077 square feet. This is the area in pink on the diagram.