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標題: [Core] Circle questions [打印本頁]

作者: luckjoe    時間: 2016-11-22 04:49 PM     標題: Circle questions

please answer the following question


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


Thank you very much
作者: bryanfu926    時間: 2016-11-22 07:55 PM

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
作者: luckjoe    時間: 2016-11-22 10:23 PM

Thank you very much




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