Algebra 1: The length of a rectangle is twice the width.

[king29]

Help please! How do I figure out the answer to this question?

The length of a rectangle is twice the width. Find the length of the rectangle if the perimeter is 42 cm.


Thanks!!

 

[jhawk555]

You need to find out the length of the rectangle whose perimeter is 42cm. They gave you a portion of the information by telling you that the length is 2 times the width.

You can draw a rectangle on your paper and plug in 2(w) for the length sides. Add a w on both ends for the width.

2w + 2W + w + w = 42

combine like terms= 6w

6w=42

divide both side by 6

w=7 (width)

to find the length you multiply 2 by 7 and get 14cm for your length.

 

[skeeter]

perimeter is 42 ...
2(L + W) = 42
L + W = 21

length is twice the width ...
L = 2W

substitute 2W for L in the perimeter equation and solve for W ... then figure out what L is.

 

[king29]

Thanks

Thanks for the assistance. I'm a Freshmen in High School and I'm struggling with this subject (Algebra1). How did you determine to get the two w's on both sides




Thank you so much

 

[Denis]

Re: Thanks

How did you determine to get the two w's on both sides

You mean to say that this simple manipulation was not explained in class? :shock: