Answer:
The length of fencing will be

Explanation:
Step 1
Find the dimensions of the rectangle
we know that
The area of a rectangle is equal to

In this problem we have

so
-----> equation A
-----> equation B
Substitute equation B in equation A

square root both sides

Find the value of b
----->

step 2
Find the length of fencing
The perimeter of a rectangle is equal to

we have


substitute
