Circumcenter of a Triangle (Circumscribing a Circle)
This applet shows the construction of the circumcenter of 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 D called? d. Constructing a circle outside triangle ABC is called what? e. Where does point D lie when the triangle is right? f. Where does point D lie when the triangle is acute? g. Where does point D lie when the triangle is obtuse? h. What is unique about the blue lines when all three sides of the triangle are congruent?