Answer: Let's call the area of Brad's rectangular backyard "A". The area of the white circle is "C". The area of the gray region, the portion of the yard that the water from the sprinkler does not reach, is "G".
We know that the sum of the areas of the white circle and the gray region is equal to the area of Brad's backyard:
C + G = A
Therefore, the expression to represent the gray region is:
G = A - C
Explanation: