Here is the result. To make everything clearer, I added a triangle to P. |
Stop the animation with a mouse click. Note that the first reflection (in line g) takes green triangle at P to the blue triangle at P*. The second reflection (in line h) takes the blue triangle to the brown triangle at P**. The double reflection is the same as rotation by an angle of 155° about the point of intersection of the two lines of reflection. Question: How is 155° related to the angle between lines g and h? |