Year level: 7

Strand: Space

Lesson length: 60 mins

As geometric explorers, students use intuition and logic to establish the side and angle properties of triangles and special quadrilaterals.

Geometric patterns Image

Achievement standard

Students classify polygons according to their features

Content descriptions

Students classify triangles, and other polygons according to their side and properties; identify and reason about relationships. AC9M7SP02

General capabilities


  • understanding geometric properties (Level 4)

Critical and Creative Thinking

  • draw conclusions and provide reasons (Level 5)

Cross-curriculum priority

Asia and Australia’s engagement in Asia

This lesson presents opportunities for assessment as described below.

Show the 321 Exit slip (slide 15) or read it out.

  • 3 geometric properties I learned today.
  • 2 things I want to learn more about.
  • 1 question I still have.

Set the following tasks and students can finish it for homework to hand in later.

  • Geometric Patterns remaining activities in the properties of quadrilaterals worksheet handed earlier.
  • Students create a concept map showing all the connections between the special quadrilaterals.
  • Acute, obtuse and right angle
  • Bisect, intersect, diagonal
  • Axis of symmetry
  • Adjacent, opposite

An area of challenge for students is recognising the properties of plane shapes when they have a different orientation. For example, a square that is displayed diagonally or an irregular five-sided shape is a pentagon.

What you need:

  • Lesson plan (Word)

  • Teacher's slides (PowerPoint)

  • Design from Asia worksheet (Word)

  • Classifying triangles template (Word, print A3)

  • Impossible triangles poster activity (Word, print A3)

  • Properties of quadrilaterals worksheet (Word)

  • Blu tac, A3/poster paper, coloured markers, ruler, pencil, eraser, scissors