I have memorized this question and I couldn't really get how I could figure it out. The question asks:

Its length is 5 times twice its width
The area is 7 square meters
Find the dimensions of this rectangle

I know its $l \times w \times h$... I don't know how I could use factoring to solve this.

Should I use gfc? Which factoring should I use? Please give me hints so I can figure out how to do this

  • $\begingroup$ $l=10w$, $A=wl=10w^{2}=9$. $\endgroup$ – Autolatry Mar 10 '15 at 12:25

The area formula of a rectangle with sides $a$ and $b$ is $A=ab$. If $a$ is the width, the text says $$\underbrace{b}_{\text{length}} = \underbrace{5\cdot}_{\text{5 times}}\ \underbrace{2\cdot}_{\text{twice}}\ \underbrace{a}_{\text{its width}} = 10a$$ also the text says $A = 7$. Now solve $$7 [m^2]=A=ab=a\cdot (10 a) = 10 a^2$$ for $a$ and substitute into $b=10a$ to get the dimensions of the rectangle. Note that $a$ and $b$ will be in $m$ (meters).

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    $\begingroup$ Im sorry it wasnt 9 I changed it! But this helped me learned how to do it so thanks! Ill solve it on my own now. $\endgroup$ – user222453 Mar 10 '15 at 12:36
  • $\begingroup$ @user222453 That's a very good attitude :) I've adapted the value of $A$ to reflect the edit. $\endgroup$ – AlexR Mar 10 '15 at 12:38

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