Constructing the Orthocenter of a Triangle in GeoGebra

This GeoGebra example demonstrates how to construct the orthocenter of a triangle, the common intersection of the three altitudes. It highlights core geometry concepts such as triangles, altitudes, perpendicular lines, intersections, angle marking, and the changing position of the orthocenter in acute, right, and obtuse triangles. The construction uses Polygon to create triangle ABC, OrthogonalLine to draw the altitude through each vertex perpendicular to the opposite side, Intersect to locate the orthocenter, Segment to connect relevant points, and Angle to label angles such as α, β, and γ. It is suitable for middle-school geometry, high-school coordinate geometry, classroom demonstrations, or student exploration of triangle centers and perpendicular relationships.