SOLUTION: The length of a rectangle is three inches more than its width. It’s area is 130 in2. Find the width and length of the rectangle.

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Question 1166619: The length of a rectangle is three inches more than its width. It’s area is 130 in2. Find the width and length of the rectangle.

Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52788) About Me  (Show Source):
You can put this solution on YOUR website!
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The dimensions are 10 cm and 13 cm.


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Comment from student :   Thank you for answering but is there a solution?



My response   In this problem,  the answer is  TOO  obvious to spend time for explanations.

                      It is the same as if I start explain you that  10*13 = 130  and  13 - 10 = 3.



Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


width: w
length: w+3
area: w(w+3)=130

If a formal algebraic solution is required, then

w%28w%2B3%29=130
w%5E2%2B3w-130=0
%28w-10%29%28w%2B13%29=0
w=10 OR w=-13

Reject the solution w=-13 because it makes no sense in the problem.

ANSWER: width = w = 10; length = w+3 = 13.

Note that to solve the problem using formal algebra, you had to factor that quadratic equation, which means finding two numbers whose difference is 3 and whose product is 130.

But that's what the original problem asked you to do.... So the formal algebra didn't save you any work.

So if formal algebra is not required, simply look at the area of 130 and see that it is 13 times 10; 13 is 3 more than 10, so you have the answer, and in only a few seconds.