This is supposed to be part of precalculus section.
http://sdrv.ms/LY22ZV
http://sdrv.ms/LY22ZV
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The only way I can think of doing this without calc is massive trial and error.
We have the equation for perimeter: 2L + 2W = 45.
And the equation for area: A = L * W
We know that L = (45 - 2W) / 2, so we can use this to alter the equation for area:
A = (45 - 2W) / 2 * W
A = (45/2)W - W^2
In order to maximize the area we take the derivative and set it equal to 0.
dA/dW = 45/2 - 2W = 0
45/2 = 2W
W = 45/4.
Now 2L + 2(45/4) = 45
2L +45/2 = 45.
2L = 45/2.
L = 45/4.
Length = 45/4, Width = 45/4. Area = 126.6ft ^ 2.
We have the equation for perimeter: 2L + 2W = 45.
And the equation for area: A = L * W
We know that L = (45 - 2W) / 2, so we can use this to alter the equation for area:
A = (45 - 2W) / 2 * W
A = (45/2)W - W^2
In order to maximize the area we take the derivative and set it equal to 0.
dA/dW = 45/2 - 2W = 0
45/2 = 2W
W = 45/4.
Now 2L + 2(45/4) = 45
2L +45/2 = 45.
2L = 45/2.
L = 45/4.
Length = 45/4, Width = 45/4. Area = 126.6ft ^ 2.
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Greatest Area will be a square
L = 45/4 and W = 45/4 ft
L = 45/4 and W = 45/4 ft