A walled rectangular garden is 24 feet wide and 42 feet long. Flowers are to be planted along the outside edges of the garden to form a border that is 2 1/2 (two and a half) feet wide all around. What will be the area of the border?
The area of the border is 20 square feet.
There are two rectangles in this problem. (See picture).
One is a rectangle covering the entire garden. The area of this we can call
The other rectangle is the space remaining in the garden inside the border of flowers. This area we can call
The area of the border is the difference between the area of these two rectangles. This area we can call
The formula for the area of a rectangle is
The area of the outer rectangle is:
The width of the inner rectangle is:
The length of the inner rectangle is
Therefore the area of the inner rectangle is:
The area of the border is the difference between the area of these two rectangles: