View source for Butterfly Theorem

Let <math>D</math> be the [[midpoint]] of [[chord]] <math>BC</math> of a [[circle]], through which two other chords <math>EH</math> and <math>FG</math> are drawn. <math>EG</math> and <math>HF</math> intersect chord <math>BC</math> at <math>I</math> and <math>J</math>, respectively. The '''Butterfly Theorem''' states that <math>D</math> is the midpoint of <math>IJ</math>.

 <geogebra>ac0eaced14d78b0f4ff370ae453962b4db309b5f</geogebra> 

==Proof==
{{solution}}

Link to a good proof : 

http://agutie.homestead.com/FiLEs/GeometryButterfly.html



==See also==
[[Category:Geometry]]
[[Category:Theorems]]