Answer: [tex]60\ ft[/tex]
Step-by-step explanation:
Given
Side length of square shape [tex]a=15\ ft[/tex]
Length of the garden is equal to the perimeter of the square i.e. 4 times the side length
[tex]\Rightarrow \text{Lenght L= }4a\\\Rightarrow L=4\times 15\\\Rightarrow L=60\ ft[/tex]
Thus, the length of the require garden is [tex]60\ ft[/tex]