Example Activity: Orthocenter of a Triangle

Below you can see a triangle ABC together with its heights. The intersection point of the three heights is called orthocenter of the triangle. Modify the dynamic construction in order to examine the orthocenter of different triangles and explore the properties of the orthocenter.

Task 1

How do you construct the orthocenter of a triangle? Write down detailed construction steps. Hint: You can use the arrow buttons of the Navigation Bar in order to redo the construction.

Task 2

You can modify the shape of the triangle by dragging its vertices with the mouse. Thereby, the orthocenter and angles change too. Try to describe the position of the orthocenter when.. a) all angles are acute. b) one angle is obtuse. c) one angle is a right angle.