how to work out the area of a circle

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    i need to know how to work out the area of a circle by using the diameter
    so if the diameter was 12.3 what would be the answer and how would you work it out?
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    divide diameter by two to get the radius.

    area = pi x radius squared
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    Have you learnt any formulas for finding the area of a circle?
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    A = \pi r^2
    d = 2r
    \Rightarrow A = \frac{1}{4}\pi d^2
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    right so just let me check ive done this question right and if i have im sorted
    the question was find the area of a circle by using diameter=14.8cm
    so i do 14.8 divided by 2=7.4 pie time 7.4 squared=172.3

    is this correct?
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    3.14*6.15 squared = 118.76 (2dp)

    I think
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    It's 172.03, but I'm guessing that was just a typing error.
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    Right, this is a rhyme (!) which will mean u never 4get this formulae again!!!

    Tweedle dum and tweedle dee,
    round the circle is pie x d,
    but if the area be declared,
    the formula is pie x r squared!

    Learn this and then use it. Obviously, d is diameter and r is radius!

    Enjoy!
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    pie r squared where r is half the diameter
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    Sounds about right 2 me. Is this work 4 2morrow lol?:p:
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    (Original post by Louismoore16)
    right so just let me check ive done this question right and if i have im sorted
    the question was find the area of a circle by using diameter=14.8cm
    so i do 14.8 divided by 2=7.4 pie time 7.4 squared=172.3

    is this correct?
    You've changed the question slightly. In your first post, you said the diameter = 12.3

    But anyway, if the diameter is 14.8cm, then the area is 172.0336... (not 172.3), but you'd probably want to round that down to 172cm squared.
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    ok thanks for all you help
    L-C-17: this is for my maths homework lol
    Tomthecool: i changed the question half way throught to 14.8 so i could check if i go it right
    and IChem: yes i ment to put 172.03 but my key is abit sticky lol
    and sorry about posting so much of the same thing, my page kept refreshing and sending.
 
 
 
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