Answer:
8 Meters
Explanation:
Even though you're looking for the length for a rectangular garden, you are actually using the Pythagorean Theorem for this since the question provides you a width and a diagonal for the rectangle.
To find the length you must use the formula:
.
You are already provided with the width, A, and the diagonal, C. So, you must find the second leg (or length) by using:






So, B=8, meaning you found the length of 8 meters.
Don't forget to use the units!
Hope this helps!