Answer:
21m
Step-by-step explanation:
So for the rectangle, do 5*6, and you will get the area of the whole backyard. Then to get the area of the grass, you do 3*3 to get 9.
Finally, to get the cement, you subtract the area of the grass from the area of the whole backyard so 30-9 to get 21.
5*6=30
3*3=9
30-9+21
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