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Which of the following expresses the area of a circle in ter
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16 May 2017, 07:45
16 May 2017, 07:45
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Which of the following expresses the area of a circle in terms of C its circumference?
A) \(\frac{C^2}{4\pi}\)
B) \(\frac{C^2}{2\pi}\)
C) \(\frac{C}{2\pi}\)
D) \(\frac{C\pi}{4}\)
E) \(\frac{C}{4\pi}\)
Re: Which of the following expresses the area of a circle in ter
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09 Oct 2017, 07:54
09 Oct 2017, 07:54
The circumference of a circle is computed as \(C = 2\pi r\), while the area of a circle is \(A =\pi r^2\).
Looking at the choices, it is easy to notice that there is no r in them. This means we have to substitute for r into the formula of the area.
In other words, from the circumference formula we get \(r= \frac{C}{2pi}\), which can be used to substitute into the area formula \(A =\pi (\frac{C}{2pi})^2 = \pi\frac{C^2}{4pi^2} = \frac{C^2}{4pi}\).
Answer A
Looking at the choices, it is easy to notice that there is no r in them. This means we have to substitute for r into the formula of the area.
In other words, from the circumference formula we get \(r= \frac{C}{2pi}\), which can be used to substitute into the area formula \(A =\pi (\frac{C}{2pi})^2 = \pi\frac{C^2}{4pi^2} = \frac{C^2}{4pi}\).
Answer A
gmatclubot
Re: Which of the following expresses the area of a circle in ter [#permalink]
09 Oct 2017, 07:54
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