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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,762

In any triangle ABC,

where R is the radius of the circumcircle.

If you are not yet familiar with the construction of a circumcircle and the angle properties of a circle, you are advised to look these up first.

The circumcircle

http://www.mathisfunforum.com/viewtopic … 40#p367140

Angle properties of a circle.

http://www.mathisfunforum.com/viewtopic.php?id=17799

Posts 6 and 7

Proof

angle AOF = half angle AOB = ACB (using the angle props)

Therefore

The rest follows by a similar argument.

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**thickhead****Member**- Registered: 2016-04-16
- Posts: 1,022

*Last edited by thickhead (2016-04-25 18:58:06)*

**{1}Vasudhaiva Kutumakam.{The whole Universe is a family.}(2)Yatra naaryasthu poojyanthe Ramanthe tatra Devataha{Gods rejoice at those places where ladies are respected.}**

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