Okay. This can be a little tricky if you dont see how to set it up.
we don't yet know the length, so lets call that x. Since we all know there are 4 sides to a rectangle lets set up the equation like this.
36 = Perimiter. Since the length is 4 ft longer lets write the expression to show that.
36= 2(4+x)+2x
x = the width, and since theres 2 lengths and 2 widths, multiply them by two. now multiply out.
36= 2(4+x)+2x => 36=8+2x+2x => 36=8+4x
now its simple algebra
36-8=4x
28=4x
x=7
since x=width, width =7 ft
since x+4=length length = 11 ft
now find the area. This is the easy part.
Area= length x width
A= 11x7
A=77 ft^2
2006-11-25 05:23:28
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answer #1
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answered by Tyler 2
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Math Question?
The length of a rectangle is 4 ft longer than its width. If the perimeter of the rectangle is 36ft, find its area.
width = (36 - 4 -4 ) divided by 4 = 7
length = 7 + 4 = 11
Area = 7 * 11 = 77ft square
2006-11-25 13:39:31
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answer #2
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answered by danieldeskbrain 2
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Let x be the width of the reactangle
length = x+4
( given length 4 ft longer than width)
Perimeter = 2*(length+width)
(given perimeter = 36 ft)
2(x+4+x) = 36
4x+8 = 36
4x = 36-8
x = 7
width= 7ft, length = 11ft
Area = 7* 11
= 77 sq.ft.
2006-11-25 13:53:26
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answer #3
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answered by george t 2
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Area = Length * Width --- (for a rectangle)
A = L * W
L = W + 4
Perimeter = 2(Length * Width) --- (for a rectangle)
P = 2(L + W)
2((W + 4) + W) = 36 --- Combine like terms...
2(2W + 4) = 36 --- Multiply 2 by the terms in the parenteses...
4W + 8 = 36 --- Subtract 8 from both sides...
4W = 28 --- Divide both sides by 4...
W = 7
Since we know that L = W + 4, and we know that W = 7:
L = 7 + 4
L = 11
A = L * W
A = 7 * 11
A = 77 feet²
2006-11-25 13:25:55
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answer #4
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answered by Anonymous
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Let the length of the rectangle be x and the width be y.
We now have two equations.
1. x+4 = y
2. 2x + 2y = 36 (perimeter)
x = y-4
Let us substitute the value of x into equation 2.
2(y - 4) + 2y = 36
2y -8 +2y = 36
4y = 44
y = 11
Then x must be 7, since x is y - 4.
Area of rectangle is length * width
= 7 * 11 = 77 sq. ft
2006-11-25 13:18:56
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answer #5
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answered by Ajam 2
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If P = 2W + 2L
And you apply this problem P = 2W + 2(W+4)
Plug in the numbers 36 = 2W + 2W + 8
Simplify the problem 36 = 4W + 8
Get the variable by itself 36 - 8 = 4W - 8
..which equals 28 = 4W
Divide by 4 to get the variable by itself
...which equals 7. So now plug 7 into the problem
W=7
L=(7+4)=11
Area=7x11=77u^2
2006-11-25 13:26:20
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answer #6
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answered by Anonymous
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Perimeter = 2*Width + 2*Length
P = 2W + 2L
L = W + 4
P = 2W + 2(W + 4) = 36
2W + 2W + 8 = 36
4W = 28
W = 7
L = 7 + 4 = 11
A = LW = 11*7 = 77
2006-11-25 13:25:13
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answer #7
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answered by kindricko 7
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just set up and equation.
2 times 4 plus 2w, plus w = 36
2006-11-25 13:18:29
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answer #8
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answered by kadmarco 4
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l=w+4
2(w+4)+2w=36
4w+8=36
4w=28
w=7'
l=11'
area=77 sft
2006-11-25 13:23:45
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answer #9
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answered by raj 7
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w=x
l=x+4
2x+2(x+4)=36
2x+2x+8
4x=28
x=7
width is 7 and length is 11
A=wl
A=77ft^2
2006-11-25 13:18:26
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answer #10
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answered by 7
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