Linking angles

Recognising angle relationships within circles is one step in deductive reasoning in circle geometry. Ordering the relationships sequentially then forms the foundation of a proof.   

A dynamic file on linking angles is available. This activity helps students explore various angle relationships and also strengthens visualisation skills.

You can assist those students who have difficulty visualising relationships in circles.

  • Highlight a shape or a pair of angles, and then erase extraneous lines. Care needs to be taken that the erasures do not make the diagram difficult to understand when returning to the original situation.
  • Draw a diagram from a set of instructions and then re-draw the same diagram but in a different sequence.
  • Colour a particular shape within a diagram and then re-draw just that shape beside the original diagram.

You can download the Linking angles slide show presentation which explains the process of working through a complex circle problem.

Curriculum links

Year 10A: Prove and apply angle and chord properties of circles