Geogebra - What angles do we find on parallel lines?

In this activity we will investigate the relationship between parallel lines and an intersecting line.

  1. Load this Geogebra file

You should see a pair of parallel lines.
  1.  Now move the the red cross +"

You should see the the red and green angle change.

  1. Use this spreadsheet to record the red and green angles of the tranversing line.
  

 

 
Questions
  1. What is the external angle of an equilateral triangle?
  2. What is radius of the circle if the diameter is 2 mm?  How did you work the answer?
  3. Does your spreadsheet data file reveal a relationship between the red and green angles?
Activities
  1. Change the circle  shape by moving point + again.  Keep changing the position until you have filled your spreadsheet data table.
  2. Save a copy of your spreadsheet in your "Maths is Amazing" folder.