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GCSE maths question watch

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    what does it mean "give your answer in the simplest form of pi"?..

    i got the answer as 24.something and i divide by pi and get 7.8?

    so is the answe 7.8pi?
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    what does it mean "give your answer in the simplest form of pi"?..
    I would assume it means give your answer in terms of \pi.

    i got the answer as 24.something and i divide by pi and get 7.8?
    It isn't clear what you are trying to do but I suspect if the result isn't an integer (whole number) you got the wrong answer. If you need a better explanation, post the question.
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    I'm assuming at GCSE this will be the volume/area of a shape/object? For example if it was the area of the circle then just work out r^2 then just plonk the \pi on the end of it, without using the \pi button on your calculator.
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    (Original post by Yacoby)
    I would assume it means give your answer in terms of \pi.


    It isn't clear what you are trying to do but I suspect if the result isn't an integer (whole number) you got the wrong answer. If you need a better explanation, post the question.
    sorry my attachment failed.. ill add it in now..it's a non calculator paper so i think i have to assume pi as 3

    so would i be right to say that

    arc length = (120/360)*3*2*6 = 12 + 12 = 24, 24/3(which i assume as pie) = 6 hence the answer is 6pi?
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    (Original post by Extricated)
    sorry my attachment failed.. ill add it in now..it's a non calculator paper so i think i have to assume pi as 3
    No. Leave pi as a symbol

    For example, the arc length AB is 6\frac{120}{180}\pi = 6\frac{2}{3}\pi =  4\pi

    So the perimeter is 6 + 6 + 4\pi = 12 + 4\pi
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    ss
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    use this formula


    works out to 38pi/3
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    (Original post by Yacoby)
    No. Leave pi as a symbol

    For example, the arc length AB is \frac{120}{180}\pi = \frac{2}{3}\pi

    So the perimeter is 6 + 6 + \frac{2}{3}\pi = \frac{38\pi}{3}
    arc length = 120/360*pi*12 isn't it? so wouldnt that make it 4pi?

    4pi + 12 =?
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    (Original post by Yacoby)
    No. Leave pi as a symbol

    For example, the arc length AB is \frac{120}{180}\pi = \frac{2}{3}\pi

    So the perimeter is 6 + 6 + \frac{2}{3}\pi = \frac{38\pi}{3}
    why is the arc length \frac{120}{180}\pi = \frac{2}{3}\pi ? :confused: i would have got it from C=pi*d=12pi then 360/120=3 so arc length is 12pi/3=4pi hence total length is 12+4pi
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    (Original post by abbii)
    why is the arc length \frac{120}{180}\pi = \frac{2}{3}\pi ? :confused: i would have got it from C=pi*d=12pi then 360/120=3 so arc length is 12pi/3=4pi hence total length is 12+4pi
    which is what i got..

    but the question asks to give it in terms of pi so i dont know how to turn the "+12" bit into pi
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    (Original post by Extricated)
    which is what i got..

    but the question asks to give it in terms of pi so i dont know how to turn the "+12" bit into pi
    i dont think you have to, cant be sure though
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    If a question asks you to give something in terms of pi, you don't have to put integers in terms of pi. It says that because the alternative way of writing the answer is as a decimal. Writing it in terms of pi means the answer is exactly right. When you write a decimal, you have rounding which means the answer is not exact.
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    (Original post by Extricated)
    arc length = 120/360*pi*12 isn't it? so wouldnt that make it 4pi?
    Yes. I messed up the equation. The post is now corrected.

    If a question asks you to give something in terms of pi, you don't have to put integers in terms of pi.
    I don't know about GCSE, but normally if it asks for something in terms of \pi and you write it as a decimal the answer marked as wrong.
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    Your formulae are very long and confusing - I imagine they're hard to remember. Think of it this way.

    If you filled in the whole circle, its diameter would be 12 (since we can see the radius is 6), and so it's circumference would be 12 \pi.

    However, we don't have the full circle. We have 120 ^{\circ} of a circle. Since a full circle is 360 ^{\circ}, then we must have \frac{120}{360} = \frac{1}{3} of a circle. So our circumference of this sector is one third of 12 \pi which is 4 \pi.

    Now we add on the two radii on the side, which equals 12 (6 each), so the total perimeter is  4 \pi + 12 \  \mathrm{cm}
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    (Original post by Yacoby)
    I don't know about GCSE, but normally if it asks for something in terms of \pi and you write it as a decimal the answer marked as wrong.
    I meant, if a question asks for "in terms of \pi," then the answer 12+4\pi is acceptable even though the 12 part doesn't contain \pi.
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    (Original post by cryptopian)
    I meant, if a question asks for "in terms of \pi," then the answer 12+4\pi is acceptable even though the 12 part doesn't contain \pi.
    yes, its still in terms of pi
 
 
 
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