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    A garage door is 4m longer that it is wide and 1 m higher than it is wide.

    The longest pole which can fit in side the garage is 7.5m long.

    How wide is the garage?

    Okay, I get the height to be x+1 , length to be x+4 and then the width to be x

    This involves quadratics but surely the length equals x+4 as it fits in the garage? Meaning that x, the width is 3.5m?

    But this is wrong according to the answers..
    any ideas?
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    the longest distance will be a diagonal. try some 3d pythagoras.
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    (Original post by Phredd)
    the longest distance will be a diagonal. try some 3d pythagoras.
    so it would be (x+4)^2 + (x+1)^2 = 7.5?
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    (Original post by madfish)
    so it would be (x+4)^2 + (x+1)^2 = 7.5?
    That's a diagonal across one side. Don't forget you are in 3 dimensions so you can have an even longer diagonal that involves the lengths of all 3 sides!
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    (Original post by davros)
    That's a diagonal across one side. Don't forget you are in 3 dimensions so you can have an even longer diagonal that involves the lengths of all 3 sides!
    ehhh I am not exactly sure what you mean :/
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    (Original post by madfish)
    ehhh I am not exactly sure what you mean :/
    Have you done 3-D co-ordinates

    Or any 3-D Pythagoras

    For example , can you find the distance between (1, 2, 4) and (3, 6, 5)
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    (Original post by TenOfThem)
    Have you done 3-D co-ordinates

    Or any 3-D Pythagoras

    For example , can you find the distance between (1, 2, 4) and (3, 6, 5)
    nope I have never done that... wasnt on my GCSE course and I have not done it at alevel
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    (Original post by madfish)
    nope I have never done that... wasnt on my GCSE course and I have not done it at alevel
    Pythagoras in 2D:

    c^2 = a^2 + b^2

    Pythogaras in 3D:

    d^2 = a^2 + b^2 + c^2

    It certainly was part of your GCSE course.
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    (Original post by madfish)
    nope I have never done that... wasnt on my GCSE course and I have not done it at alevel
    Ok

    Well the diagonal in 3_D space is given by

    d^2 = a^2 + b^2 + c^2
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    (Original post by madfish)
    nope I have never done that... wasnt on my GCSE course and I have not done it at alevel
    Are you self-teaching or do you have a teacher who can go through this with you?

    There's basically a very simple extension of Pythagoras's theorem from 2 dimensions to 3 dimensions that will help you solve this, but you probably need to do some practice questions with it to see what's going on.
 
 
 
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