In the comment of the other answer, you said that the rectangle is 24 x 18 ft.
First, we have to find out how many square feet that is, and then we can convert it to square yards.
The area of a rectangle is the length multiplied by the width.
A = l x w
A = 24 x 18
A = 432 square feet
To find out how many square yards that is, we divide it by 3, because 1 yard is 3 feet.
432 ÷ 3 = 144
The area of a 24x18ft rectangle is 144 square yards.