Question

Need help.

The Andersons decided to fence in part of their yard to use as a garden. They bought 56 ft. of fencing, and they know they want the length to be 18 ft. If they use all of the fencing, what would the width be?

Answer 1

Answer: width is 10 feet

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Work Shown:

L = length = 18

W = width = unknown

P = perimeter of rectangle = 56

P = L+L+W+W

P = 2L+2W

P = 2*18+2W ... plug in given length

P = 36+2W

36+2W = P

36+2W = 56 ... plug in given perimeter

36+2W-36 = 56-36 ... subtract 36 from both sides

2W = 20

2W/2 = 20/2 ... divide both sides by 2

W = 10

This rectangle is 10 ft by 18 ft.

As a check,

L+L+W+W = 18+18+10+10 = 36+20 = 56

so we get the proper perimeter

note: this assumes that there is no bit of fencing that goes to waste, there are no gaps, or there are no overlapping portions.