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  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

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#1 2007-05-19 02:49:47

Identity
Member
Registered: 2007-04-18
Posts: 934

Geometry :[

Image attached is the problem... thanks...

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#2 2007-05-19 13:01:01

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: Geometry :[

Let O be the centre of the circle. Then

Since ΔAOC is isosceles,

And from

and

we have

Hence ΔBAT and ΔACT are similar.

Note that BT can cut the cricle above or below the centre O.

Last edited by JaneFairfax (2007-05-19 22:19:51)

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#3 2007-05-19 21:18:46

Identity
Member
Registered: 2007-04-18
Posts: 934

Re: Geometry :[

Thanks again Jane!

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#4 2007-05-22 21:05:10

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,711

Re: Geometry :[

A little birdie told me about: http://www.matematyka.org/forum/viewtopic.php?t=36307


"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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#5 2007-05-22 22:51:46

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: Geometry :[

Haha! The equation in the second reply (third post) y[sup]2[/sup] + x[sup]2[/sup] = r[sup]2[/sup] + 12[sup]2[/sup] is wrong. tongue

I forgot that a radius bisects a chord if and only if it is perpendicular to it. At least I discovered a pair of similar triangles in the setup.

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