Angles with Parallel or Perpendicular Lines 
Angles with parallel lines
What are relationships between the angles created by parallel lines?
Made by Antonija Horvatek with the GeoGebra program
Follow the instructions in the applet.
Angles with perpendicular lines  investigation Use the applet below to investigate the relationships between angles with perpendicular lines.
Made by Antonija Horvatek with the GeoGebra program
Start by clicking the buttons down in the applet.
Angles with perpendicular lines  exercise Use the applet below to check if you understood the relationships between angles with perpendicular lines.
Made by Antonija Horvatek with the GeoGebra program
Follow the instructions in the applet. Note: If applets don't work correctly, try to use another web browser (Chrome, Mozilla Firefox, Internet Explorer...) or change some properties in the web browser you use. Also, you can try upgrade your web browser.
