Answer:
PartA
P = 4a
Part B
60 = P fence + 2a
60 = 6a
Part C
40
Step-by-step explanation:
We are building a fence so we are finding perimeter.
Adding the 3 sides
P = a+b+a
P = 2a+b
It is twice as long as it is wide
b= 2a
Replace in the equation for perimeter
P = 2a+(2a)
P = 4a
Part B
We know the perimeter is 60 for the entire backyard
The perimeter of the backyard is the fence plus the longer side
60 = P fence + b
Replacing b
60 = P fence + 2a
We know the equation for the perimeter of the fence is
60 = 4a + 2a
Combing like terms
60 = 6a
Part C
Solve for a and b
60 = 6a
Divide each side by 6
60/6 = 6a/6
10 =a
P fence = 4a
P = 4(10) = 40
