Question 1115764: if the area of a rectangle=84ft^2 find its dimensions
area of a rectangle is L*W
W=?
L=5ft-w Found 2 solutions by rothauserc, Alan3354:Answer by rothauserc(4718) (Show Source):
You can put this solution on YOUR website! I think you meant to state the problem this way,
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width(w) is 5ft less than the length(l)
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l * (l-5) = 84
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l^2 -5l = 84
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l^2 -5l -84 = 0
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(l-12) * (l+7) = 0
:
l = 12 or l = -7
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we reject the negative value for l
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l = 12
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w = 12 -5 = 7
:
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dimensions of the rectangle are length = 12 feet and width = 7 feet
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********** stated problem *********
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(5-w) * w = 84
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5w -w^2 = 84
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w^2 -5w +84 = 0
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the discriminant is
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square root((-5)^2 -4 * 1 *84) =
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square root(25 -336) =
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square root(-311) =
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an imaginary number involving i(square root(-1)
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this problem has no real solution
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You can put this solution on YOUR website! if the area of a rectangle=84ft^2 find its dimensions
area of a rectangle is L*W
W=?
L=5ft-w
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L+W = 5
The max area is of a square --> L = W = 2.5
Max area = 6.25 sq ft
84 sq ft is not possible.
