Thales' theorem

When you press the start button the top corner of the triangle begins to move on the outline of the circle.

  1. What can you say about all the triangle edges originating in the center of the circle?
  2. Which type are both the triangles - the red and the blue one?
  3. Compare the two red arcs to each other. Do the same for the blue ones.
  4. Consider the triangle composed of the red and the blue triangle. Set up the formula for the sum of angles of the combined triangle.
  5. Calculate the sum of one blue and one red angle.
  6. Which type is the combined triangle?