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[Core] Circle questions

luckjoe

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1^# 大中小發表於 2016-11-22 04:49 PM (第 2706 天) 只看該作者

Circle questions

please answer the following question

https://www.flickr.com/photos/124898006@N08/30804202710/in/dateposted-public/

Thank you very much

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bryanfu926

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2^# 大中小發表於 2016-11-22 07:55 PM (第 2706 天) 只看該作者

[隱藏]

Slope of CD = [- 4.5 - (-7.5)]/ (6-13.5) = -2/5
AB perpendicular to CD, therefore Slope of AB x Slope of CD = -1
Slope of AB = 5/2
Let B be (x,y)
y - (-4.5) / x - 6 = 5/2
2y + 9 = 5x - 30
5x - 2y - 39 = 0 --- (1)
x^2 + y^2 - 12x + 9y - 9 = 0 --- (2) (given)
Solving for (1) and (2), we get x = 9, y = 3

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luckjoe

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3^# 大中小發表於 2016-11-22 10:23 PM (第 2706 天) 只看該作者

Thank you very much

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