Dynamic Geometry: Orthocenter
The interactive figure above, created with GeoGebra,
shows a triangle ABC with the three altitudes AH_{1}, BH_{2}, and CH_{3} intersecting at
a point H, called orthocenter.
To explore (show / hide): tap a check box.
To stop/play the animation: tap the icon in the
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upper right corner.
To manipulate the interactive figure: tap and drag points or lines.
GeoGebra
GeoGebra is free and multiplatform 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.
