Respuesta :
Answer:
The total cost of the rocks needed for the border is $538.80.
Step-by-step explanation:
The length of the lawn is = 150 feet
The width of the lawn is = 80 feet
The gravel border will be 6 feet wide from all sides.
So, bigger rectangle will have length = [tex]150+12=162[/tex] feet
And width will be = [tex]80+12=92[/tex] feet
Area of the bigger rectangle = [tex]162\times92=14904[/tex] square feet
Area of the smaller rectangle = [tex]150\times80=12000[/tex] square feet
So, area of the gravel area will be = [tex]14904-12000=2904[/tex] square feet.
Now depth of gravel is 2 inches. So, volume will be area of gravel times depth.
We will convert 2 inches in feet.
12 inches = 1 feet
So, 2 inches = [tex]\frac{2}{12}=0.167[/tex] feet
[tex]2904\times0.167=484.97[/tex] cubic feet
1 cubic foot = 0.037037 cubic yard
So, 484.97 cubic feet = [tex]484.97\times0.037037=17.96[/tex] cubic yards
Now cost of gravel per cubic yard is $30.
So, total cost will be = [tex]30\times17.96=538.80[/tex] dollars
Therefore, the total cost of the rocks needed for the border is $538.80.
Please find attached the diagram of the lawn.
![Ver imagen chisnau](https://us-static.z-dn.net/files/d12/4731dd99e897826bb3c795927b877867.jpg)