Answer:
A backyard farmer wants to enclose a rectangular space for a new garden. She has purchased 80 feet of wire fencing to enclose 3 sides, and will put the 4th side against the backyard fence. Find a formula for the area enclosed by the fence if the sides of fencing perpendicular to the existing fence have length
L.
In a scenario like this involving geometry, it is often helpful to draw a picture. It might also be helpful to introduce a temporary variable,
W, to represent the side of fencing parallel to the 4th side or backyard fence.
Since we know we only have 80 feet of fence available, we know that
L + W + L = 80, or more simply, 2L + W = 80. This allows us to represent the width, W, in terms of L: W = 80 – 2L
Now we are ready to write an equation for the area the fence encloses. We know the area of a rectangle is length multiplied by width, so
A = LW = L(80 – 2L)
A(L) = 80L – 2L2
This formula represents the area of the fence in terms of the variable length
L.
Step-by-step explanation:
it's in the answer
