Angles with perpendicular lines - exercise

Author:
ahorvatek
Use the applet below to check if you understood the relationships between angles with perpendicular lines.
Follow the instructions in the applet. Choose different values of the angle α, then use the 'angle' check boxes and try to guess the values of the angles. Also, you can move the vertex of the shown angles to check if their sides are perpendicular to the sides of the angle α.