Orthocenter of a Triangle - Dynamic Construction

This GeoGebra example dynamically demonstrates the classic geometric fact that the three altitudes of a triangle are concurrent at the orthocenter. It covers the core concept of the orthocenter, the definition of altitudes, and the idea of concurrency. The construction uses the Polygon command to create triangle ABC, OrthogonalLine to draw perpendiculars from each vertex to the opposite side, Intersect to find the intersection points of these altitudes, and Line/Angle tools to label segments and angles, with a text object for explanation. Suitable for middle and high school geometry classes, this interactive model helps students visualize how the orthocenter moves inside, on, or outside the triangle depending on whether the triangle is acute, right, or obtuse, and supports inquiry-based learning about triangle centers.