SOLUTION: This is a 4th grade problem A rectangle is 7 meters long. the perimeter is 24 meters. What is the width of the rectangle? Know the answer but not sure how to write the answer?

Algebra ->  Rectangles -> SOLUTION: This is a 4th grade problem A rectangle is 7 meters long. the perimeter is 24 meters. What is the width of the rectangle? Know the answer but not sure how to write the answer?      Log On


   

Question 958193: This is a 4th grade problem
A rectangle is 7 meters long. the perimeter is 24 meters. What is the width of the rectangle? Know the answer but not sure how to write the answer?
Found 3 solutions by macston, josmiceli, Theo:
Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
L=length; W=width; P=perimeter
P=2(L+W) Divide each side by 2.
P/2=L+W Subtract L from each side.
(P/2)-L=W Plug in values.
(24m/2)-7m=W
12m-7m=W
5m=W ANSWER: The width is 5 meters.



Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Length = +7+ m
The perimeter is twice the length
plus twice the width
--------------------
Given:
length = +7+ m
perimeter = +24+ m
---------------------
+24+=+2%2AL+%2B+2%2AW+
+24+=+2%2A7+%2B+2%2AW+
+24+=+14+%2B+2%2AW+
Subtract +14+ from both sides
+10+=+2%2AW+
Divide both sides by +2+
+W+=+5+ m
----------------
The width is 5 meters

Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
Perimeter of a rectangle is 2 times the length plus 2 times the width.

You know the length is 7, so 2 times the length is 14.

Since the perimeter is 2 times the length plus 2 times the width, and 2 times the length is 14, then the perimeters is equal to 14 plus 2 times the width.

You know the perimeter is 24 meters.

this means that 24 is equal to 14 plus 2 times the width.

since the perimeter is equal to 2 times the length plus 2 times the width, if you take away 2 times the length, you are left with 2 times the width.

perimeter is equal to 24.
2 times the length is equal to 14.
take away 14 from 24 and you are left with 10.

this means that two times the width must be equal to 10.

if 2 times the width is equal to 10, then the width must be equal to 5 because 2 * 5 is equal to 10.

your answer is that the width is equal to 5.

you confirm by taking 2 times 7 plus 2 times 5 which is equal to 14 plus 10 which is equal to 24 which is equal to the perimeter.

the logic is very similar to what you do algebraically but it's not called that because the fourth graders haven't learned algebra yet and so they can't speak that language.