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# What is the area of the circle above with center O?

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Re: What is the area of the circle above with center O? [#permalink]
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himanshurajawat wrote:
Hi Archit3110,

How did you calculate '270' as the angle around C?

Posted from my mobile device

see angle BOA= 90* and around center total 360 so angle for arc BCA ; 360-90 ; 270*
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Re: What is the area of the circle above with center O? [#permalink]
Bunuel wrote:

What is the area of the circle above with center O?

(1) The area of OAB is 50.

(2) The length of arc ACB is $$15\pi$$.

Attachment:
image794.png

Asked: What is the area of the circle above with center O?

(1) The area of OAB is 50.
$$r^2/2 = 50$$
r = 10
$$Area = 100\pi$$
SUFFICIENT

(2) The length of arc ACB is $$15\pi$$.
$$3/4C = 15\pi$$ where C = circumference
$$C = 2\pi r = 20 \pi$$
r = 10
$$Area = 100\pi$$
SUFFICIENT

IMO D
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Re: What is the area of the circle above with center O? [#permalink]

What does statement 1 implies? Is it the area of the triangle or the area of the segment?
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Re: What is the area of the circle above with center O? [#permalink]
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himanshurajawat wrote:

What does statement 1 implies? Is it the area of the triangle or the area of the segment?

It is odd that it is not mentioned whether OAB is the triangle or the sector. An official question would specify clearly. Here, I would just assume that it is the triangle because there is no mention of pi here.
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Re: What is the area of the circle above with center O? [#permalink]
himanshurajawat wrote:

What does statement 1 implies? Is it the area of the triangle or the area of the segment?

It is odd that it is not mentioned whether OAB is the triangle or the sector. An official question would specify clearly. Here, I would just assume that it is the triangle because there is no mention of pi here.

Original question mentions triangle OAB, I copied incorrectly. Edited. Thank you!
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Re: What is the area of the circle above with center O? [#permalink]
Bunuel wrote:

What is the area of the circle above with center O?

(1) The area of triangle OAB is 50.

(2) The length of arc ACB is $$15\pi$$.

Attachment:
image794.png

Video Explanation

Re: What is the area of the circle above with center O? [#permalink]
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