For this case we can pose the problem as a rectangle triangle.
We know the hypotenuse and one side of the triangle.
Therefore, the other side is given by:
10 ^ 2 = 6 ^ 2 + x ^ 2
Clearing x we have:
x ^ 2 = 10 ^ 2-6 ^ 2
x = root (10 ^ 2-6 ^ 2)
x = 8 feet
Answer:
The length in feet of the garden is:
x = 8 feet