SOLUTION: I have presented this problem in the past and have not gotten a clear understanding of what is the correct formula and steps to take to get the correct answer. Please Help!!! Th

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Let's put down some formula first.


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.
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Now let's use the information we have,
"The perimeter of a rectangle is 20 meters"

1.
"If the length is increased by four times the width, the sum is 19 meters"
2.
Now you have 2 equations with 2 unknowns.
Use eq. 1,


Now substitute into eq. 2,




Then from eq. 1,



Then from those two,

You can put this solution on YOUR website!
The perimeter of a rectangle is 20 meters.
If the length is increased by four times the width, the sum is 19 meters.
What are the dimensions of the rectangle? What is its area?
:
Let L = the length of the rectangle
Let W = the width
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Write an equation for each statement
"The perimeter of a rectangle is 20 meters."
2L + 2W = 20
We can simplify this divide by 2, results:
L + W = 10
W = (10-L); this form for substitution
:
"the length is increased by four times the width, the sum is 19 meters."
L + 4W = 19
Substitute W with (10-L)
L + 4(10-L) = 19
L + 40 - 4L = 19
L - 4L = 19 - 40
-3L = - 21
L =
L = +7m is the length
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What are the dimensions of the rectangle?
find the width
W = 10 - L
W = 10 - 7
W = 3m
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Dimensions: 7 by 3
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What is its area? 7 * 3 = 21 sq/m
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Check solutions by finding the perimeter with these dimensions
2(7) + 2(3) = 20