493 reputation
1310
bio website cnblogs.com/graphics
location Beijing, China
age 33
visits member for 1 year, 11 months
seen Mar 25 at 8:59

I like computer graphics and DirectX


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comment How do you find the center of a circle with a pencil and a book?
@wim This is also a good solution!
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awarded  Popular Question
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comment How do you find the center of a circle with a pencil and a book?
The second way was not true, you have no way to fold the circle exactly half, if you can do that, it means you already get the diameter.
Oct
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comment How do you find the center of a circle with a pencil and a book?
Excellent, this one didn't use the corner of the book, I like it!
Oct
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comment How do you find the center of a circle with a pencil and a book?
The two points of intersection from these two lines define a diameter. Why?
Oct
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comment How do you find the center of a circle with a pencil and a book?
@Will Jagy, thanks for the link, but I think even the book can not cover the circle, it still works, since we can extend the line with the edge of the book. the key point is then the book has the corner as right-angle.
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awarded  Good Question
Oct
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revised How do you find the center of a circle with a pencil and a book?
added 11 characters in body
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comment How do you find the center of a circle with a pencil and a book?
That's not the case, in that case, the pencil and the book was uselessness.
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comment How do you find the center of a circle with a pencil and a book?
How can you fold in half? the paper is not transparent, and you can not see the backside.
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awarded  Nice Question
Oct
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comment How do you find the center of a circle with a pencil and a book?
Yes you can fold it, but how can you make sure you are folding along the diameters?
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awarded  Commentator
Oct
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comment How do you find the center of a circle with a pencil and a book?
Thank you very much for your kindly reminder, I will keep it for a while next time.
Oct
2
revised How do you find the center of a circle with a pencil and a book?
edited tags