Orthocenter of a Triangle
This applet shows the construction of the orthocenter in a triangle.
Move points A, B and C and notice what happens to the triangle. Answer the following questions: a. What are the blue lines in the construction called? b. How are those blue lines constructed? c. What is point O called? d. Where is point O when the triangle is acute? e. Where is point O when the triangle is obtuse? f. Where is point O when the triangle is right? g. What is unique about the blue lines when all three sides of the triangle are congruent?