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Really need some help on Quadratic Formula's ect

  1. May 13, 2004 #1
    Really need some help on Quadratic Formula's ect ......

    Heres the question .... your help is greatly needed and appreciated ...

    Markita wants to fence a rectangular plot of land along side the shore of a lake. Only 3 sides must be fenced, since the lake will form teh lake will form teh fourth side. Markita had 100m of fencing, and she wants the plot of land to have an area of 500m^2 (squared). Find teh demensions of the plot of land, to the nearest tenth of a metre. Expalin and justify your solution.

    Theres thequestion , lmk what u can do to help me out ... Thx
  2. jcsd
  3. May 13, 2004 #2
    Let the length of the fence be L and the width be w.

    Can you find an equation relating area to L and w?

    Can you find an equation relating perimeter to L and w?

    Can you solve this system of equations?

  4. May 13, 2004 #3
    Hey ... i ahve absolutley no idea how to even start this question, we have a test on a question like this tomrow and thought i coem here to get teh proper format ect basically looking for teh compltete answer so if u can help me on that i woudl greatly aprreacite it.
  5. May 13, 2004 #4
    I just told you how to start the question. If you're not willing to put in effort to attempt to solve it, then looking at the answer isn't going to help you on the test anyway.

  6. May 13, 2004 #5
    furhtermore... Whats the maximum area that this fence can enclose? :P give it some thought.
  7. May 14, 2004 #6


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    What are the formulas for area and perimeter of a rectangle ? Use the area formula to write the length(L) in terms of the breadth(W). So now, your length and breadth are written in terms of just one variable. How is the total length of the fence related to the length and breadth. Write this down and subtitute from your previous result. That should give you an equation with terms where the variable is sometimes in the numerator and sometimes in the denominator. Multiply thoughout by the variable to remove it from the denominator. You now have a quadratic equation. Solve this in the required manner.
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