Answer: 272 square feet
Explanation:
We must find the total area of the backyard then subtract the area of the not allowed area from it. Clearly, the length and width of the backyard is 22 and 17ft respectively, so the total area is 22*17=374ft^2.
The restricted space can be seen as two rectangles, both with width 3 and length 17, making their area 2(17*3) =102
374-102= 272