Orthocenter Demonstration by Ngan Chiu Yeung

This example demonstrates the geometric properties and construction method of the orthocenter in a triangle. It involves core mathematical concepts such as perpendicular lines, angles, similarity transformations, and trigonometry. The construction uses GeoGebra commands like Polygon, OrthogonalLine, Angle, and Intersect to draw the triangle and determine the orthocenter. Suitable for high school mathematics teaching or for geometry enthusiasts to learn.