To solve this problem yo must apply the proccedure shown below:
1. You must use the formula applied to calculate the area of the garden.
[tex]A=bh[/tex]
2. You know the value of the area ([tex]127^{\frac{1}{2}}ft^{2}=127.5ft^{2}[/tex] and the value of the heigth ([tex]8^{\frac{1}{2}}ft=8.5ft[/tex] , therefore, you only need to solve for the base:
[tex]b=\frac{A}{h}\\b=\frac{127.5ft}{8.5ft}\\b=15ft[/tex]
The answer is: 15 feet.