Question

Use any problem solving strategy to solve the following problem. suppose you are fencing a rectangular dog pen with a 100ft of fencing. The pen is to be 10 feet longer than it is wide. what are the dimensions of the pen?

Answer 1

let x be the width, then x+10 will be its length
the perimeter of the pen is 100 = 2x + 2(x+10)
solve for x:
100 = 2x + 2x +20
80 = 4x
x = 20
x+10 = 30

so the width = 20 ft and length = 30 ft

Answer 2

100 ft of fencing means that the total perimeter of the fence is 100ft. Now if you take the width of the fence to be x then the length x + 10

Answer 3

The formula for a rectangle is P = 2w + 2l
so 100 = 2x + 2(x + 10)
100 = 2x + 2x + 20...distribute the 2
100 = 4x + 20....Add like terms (2x + 2x = 4x)
4x = 80....subtract 20 from both sides
x = 20...divide both sides by 4.
Pen is x + 10 = 20 + 10 = 30ft