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Topic: ABCD is a cyclic quadrilateral (Read 3179 times) |
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tony123
Junior Member
Posts: 61
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ABCD is a cyclic quadrilateral
« on: Nov 19th, 2007, 9:34am » |
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ABCD is a cyclic quadrilateral, with side AD= d where d is the diameter of the circle. AB= a BC= a and CD= b If a, b and d are integers a =\= b (a)prove that d cannot be a prime number . (b)determine the minimum value of d.
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« Last Edit: Nov 19th, 2007, 1:20pm by tony123 » |
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pex
Uberpuzzler
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Posts: 880
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Re: ABCD is a cyclic quadrilateral
« Reply #1 on: Nov 19th, 2007, 9:37am » |
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on Nov 19th, 2007, 9:34am, tony123 wrote:ABCD is a cyclic quadrilateral, with side AD= d where d is the diameter of the circle. AB= a BC= a and CD= b If a, b and d are integers a ≠ b (a)prove that d cannot be a prime number . (b)determine the minimum value of d. Online |
| Not again... what is ≠ ? And does the "Online" at the end come from wherever you copied it from?
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thinktank
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Posts: 10
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Re: ABCD is a cyclic quadrilateral
« Reply #3 on: Nov 20th, 2007, 7:48am » |
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The least value of d I think is 9 The proof for d not being a prime is also not that difficult...use the equation d(d-b)=2a2
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« Last Edit: Nov 20th, 2007, 7:55am by thinktank » |
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pex
Uberpuzzler
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Posts: 880
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Re: ABCD is a cyclic quadrilateral
« Reply #4 on: Nov 20th, 2007, 8:26am » |
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on Nov 20th, 2007, 7:48am, thinktank wrote:The least value of d I think is 9 The proof for d not being a prime is also not that difficult...use the equation d(d-b)=2a2 |
| Aha... but isn't 8*(8-7)=2*22?
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