Angle facts with parallel lines

This type of activity is known as Demonstration. Please read the guidance notes here, where you will find useful information for running these types of activities with your students.

1. Demonstration

  • I begin by displaying the Geogebra page with two angles on each set of parallel lines highlighted
  • I explain the relationship between these two angles (e.g. “these are alternate angles”)
  • I then vary the conditions of one set of angles using the suggestions below, but always keep one set of angles the same for comparison
  • Each time, I ask the students to consider if the relationship is still the same of if it has changed
  • I then explain before varying again
  • I ensure I include a mixture of examples and non-examples
  • I will use this tool to introduce students to alternate, corresponding and co-interior/allied angle facts
  • At the end I ask students to discuss the rule with their partners, and then we have a class discussion

 

2. Possible variations

  • Vary angle highlighted by clicking on the check boxes
  • Vary the width and orientation of the parallel lines by dragging the intersection of the lines passing through C and D
  • Vary the orientation of the second set of angles by dragging the intersection of the lines passing through M and K

Click here to open the page full screen in Geogebra