find perimeter, if length is twice width, area is 200

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rddlkmbrly
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find perimeter, if length is twice width, area is 200

Postby rddlkmbrly » Wed Mar 04, 2009 12:54 am

what is the formula to find the perimeter of a rectangle: the length is twice it's width and the area is 200 ft sq.

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stapel_eliz
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Postby stapel_eliz » Wed Mar 04, 2009 3:00 am

rddlkmbrly wrote:what is the formula to find the perimeter of a rectangle: the length is twice it's width and the area is 200 ft sq.

"The formula" is what you need to come up with! :wink:

Since length is defined in terms of width, pick a variable for the width. Then translate the relationship of "the length is twice the width" into a mathematical expression.

Take the geometrical formula for the area "A" of a rectangle with width "w" and length "L", and plug your variable, your expression, and the given value for A into this formula.

Solve for the width. Back-solve for the length. Then plug these values into the formula for the perimeter P of a rectangle with width w and length L.

If you get stuck, please reply showing how far you have gotten. Thank you! :D

wibblyangelica
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Re: find perimeter, if length is twice width, area is 200

Postby wibblyangelica » Wed Mar 04, 2009 2:34 pm

P = 2L+2W


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