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Math Help - fence!!

  1. #1
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    help please!!

    Please help with the questions below:

    http://img180.imageshack.us/img180/8...0600000kz1.jpg
    http://img216.imageshack.us/img216/9...0600001fj6.jpg

    The correct answers are supposed to be the following, but I dont understand how?

    1. Fence B will need 13m 40cm more
    2. Curtain rail of 200cm needs 'd' & Curtain rail of 160cm needs 'a'

    Thanks
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  2. #2
    MHF Contributor Quick's Avatar
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    Here is Fence A
    Code:
             26.2
     _____________________
    |                    |
    |                    |
    |a                   |19.5
    |                    |
    |       b       2    |
    ----------------:____|
                      9.6
    using logic we find that

    a=19.5-2

    and b=26.2-9.6

    can you continue from there?
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  3. #3
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    dont get it....
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  4. #4
    MHF Contributor Quick's Avatar
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    Quote Originally Posted by technics
    dont get it....
    That's unfortunate...

    Alright if you had a rectangle with a side of 5, you would say the opposite side is 5.

    now look at the rectangle-like thing.

    Code:
             26.2
     _____________________
    |                    |
    |                    |
    |a                   |19.5
    |                    |
    |       b       2    |
    ----------------:____|
                      9.6
    now we can look at the side that says 26.2 and conclude that b+9.6=26.2

    Code:
             26.2
     _____________________
    |                    |
    |                    |
    |a                   |19.5
    |                    |
    |       b       2    |
    ----------------:____|
                      9.6
    :---------26.2-------:
    Now if b+9.6=26.2 than of course b=26.2-9.6=16.6

    can you do side a?
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  5. #5
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    i dont have a clue about the way you are doing this please can you advise if the suggested answer is correct?
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  6. #6
    Member Glaysher's Avatar
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    Horizontally along the top is 26.2 long

    Going horizontally along the bottom is the side b and the side 9.6 long

    They both move the same distance horizontally

    So they both add up to 26.2

    So to find b take 9.6 away from 26.2

    b= 26.2 - 9.6
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  7. #7
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    that gives 16.6 but the suggested answer is different!?
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  8. #8
    MHF Contributor Quick's Avatar
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    Quote Originally Posted by technics
    that gives 16.6 but the suggested answer is different!?
    You're misguided

    b is NOT the perimeter or the answer, b is a side of the rectangle (look at my earlier illustrations)
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  9. #9
    Super Member

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    Hello, technics!

    Are you really having difficulty with the diagrams in the fencing problem?

    Can you do this one?
    Code:
          : - - - - 8 - - - - - :
          *---------------------*
          |                     |
          |                     |
          |       *-------------*
          |       |     ↑
          |       |   How long is this wall?
          *-------*
          : - 3 - :

    And I don't understand their answers at all . . .

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  10. #10
    MHF Contributor Quick's Avatar
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    Quote Originally Posted by Soroban

    And I don't understand their answers at all . . .

    I agree, are you sure the answer isn't 11m 40cm?
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  11. #11
    Grand Panjandrum
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    Quote Originally Posted by technics
    Please help with the questions below:

    http://img180.imageshack.us/img180/8...0600000kz1.jpg
    http://img216.imageshack.us/img216/9...0600001fj6.jpg

    The correct answers are supposed to be the following, but I dont understand how?

    1. Fence B will need 13m 40cm more
    2. Curtain rail of 200cm needs 'd' & Curtain rail of 160cm needs 'a'

    Thanks
    To do the second we would need to know the rules you are supposed to
    apply about how much "extra" curtain you need. These are not absolute
    rules and so we cannot give you a single answer.

    The only absolute rule that applies here is the the total width of the
    two curtains should be at least as big as the length of the curtain pole.

    RonL
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  12. #12
    Grand Panjandrum
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    In the case of the first of these problems the total fence needed for the fields
    is equal to twice the total width plus twice the total length of the fields. The
    fact that they are L-shaped is irrelevant, what is important is the total run
    of timber lengthwise and widthwise.

    The first field has a width of 19.5m and a length of 26.2m.

    The second fields has a width of 11.6+7.4=19m m, and a length of 32.4m

    RonL
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  13. #13
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    got it, can you please however explain how to arrive at the sugggested answer?
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  14. #14
    MHF Contributor Quick's Avatar
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    Quote Originally Posted by technics
    got it, can you please however explain how to arrive at the sugggested answer?
    My computer says the suggested answer is wrong ...
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  15. #15
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    I too get 11.4 but the question says that the correct answer is 13.40??
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