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 [tex]A=\frac{(a+b)*h}{2}[/tex]
a and b are the lenghts of the parallel sides and h is the height.
From the picture [tex]a=10*5=50\\b=9*5=45\\h=8*5=40[/tex]
Then we plug into our formula
[tex]A=\frac{(a+b)*h}{2} =\frac{(50+45)*40}{2} = 1200[/tex] 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:
[tex]\frac{1900}{225} =8.444...[/tex] bags
This is more than 8 bags so they will need 9 bags to cover their entire yard.
