# Dynamic Geometry Problem 894: Triangle, Angle, 60 degrees, Incenter, Midpoint, Parallel Lines. GeoGebra, Step-by-step Illustration

The dynamic figure blow shows a scalene triangle ABC, where angle B = 60 degrees. I is the incenter, D is the midpoint of BC, and E is the midpoint of AB. The extension of DI intersects BA at point M, and the extension of EI intersects BC at point N. Prove that AN is parallel to MC.

## Poster of Problem 894 using iPad Apps

### Classroom Resource:Interactive step-by-step animation using GeoGebra

This step-by-step interactive illustration was created with GeoGebra.

• To explore (show / hide): click/tap a check box.
• To stop/play the animation: click/tap the icon in the lower left corner.
• To go to first step: click/tap the "Go to step 1" button.
• To manipulate the interactive figure: click/tap and drag the blue points or figures.

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.