Go Geometry Problems

Dynamic Geometry Problem 895: Triangle, Incircle, Tangency Points, Parallel lines, Collinear Points. GeoGebra, HTML5 Animation for Tablets (iPad, Nexus). Levels: School, College, Mathematics Education

The dynamic figure above shows a triangle ABC, D, E, and F are the tangency points with the incircle I. DG and EH are parallel to AB so that G is on EF and H is on FD extended. If DE and GH meet at K, prove that C,K,F are collinear. 
 

Dynamic Geometry of Problem 895
The interactive demonstration above was created with GeoGebra.

To stop/play the animation: tap the icon in the lower left corner.
To reset the interactive figure to its initial state: tap the icon in the upper right corner.
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GeoGebra
GeoGebra is free and multi-platform dynamic mathematics software for all levels of education that joins geometry, algebra, tables, graphing, statistics and calculus application, intended for teachers and students. Many parts of GeoGebra have been ported to HTML5. It has received several educational software awards in Europe and the USA.
 

Dynamic Geometry Problem 895: Triangle, Incircle, Tangency Points, Parallel lines, Collinear Points. HTML5 Animation for Tablets
 

 

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