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A farmer wants to set up a pigpen using 40ft of fence to enclose a rectangular area of 51 square feet. Find the dimensions of the pigpen.

User Bhupendra
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1 Answer

4 votes

Answer:

The sides of the pigpen are 3 by 17

Explanation:

Perimeter of pigpen => 2x + 2y = 40

Area of pigpen => xy = 51 (this is assuming x = length, and y = width)

Let's isolate "y" for the first equation;

2x + 2y = 40

2(x + y) = 40

x + y = 20

y = 20 - x

xy = x(20 - x) = 51 = 51

20x - x^2 = 51

x^2 - 20x + 51 = 0

According to the quadratic equation =>

x = ( - (- 20) + √(- 20)^2 - 4 * 1 * 50 ) / 2 * 1 = 17

x = ( - (- 20) - √(- 20)^2 - 4 * 1 * 50 ) / 2 * 1 = 3

The dimensions of the pigpen are actually 17 by 3

Proof: 17(3)= 51, 2(17) + 2(3) = 40

User Kamil Jarosz
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