Altitudes in Triangles

This example demonstrates the properties of the three altitudes in a triangle and their intersection point, the orthocenter. It involves core mathematical concepts like orthocenter, congruence, function graph, planes, and secant line. The construction uses GeoGebra commands Polygon with objects A, B, C for vertices and t1, c, a, b for auxiliary lines and calculations. Suitable for high school mathematics education to understand the properties of triangle altitudes and the application of the orthocenter.