Answer:
9 bags
Step-by-step explanation:
First we will need to calculate the area of their entire backyard, which has a shape of trapezium.
So the formula for the area of a trapezium is
a and b are the lenghts of the parallel sides and h is the height.
From the picture
Then we plug into our formula
square feet
To get the number of bags required we just simply divide the aree of their entire yard by the space that 1 bag covers. We get:
bags
This is more than 8 bags so they will need 9 bags to cover their entire yard.
