Teacher guide reSolve: Mechanical Linkages: Similar Triangles

TLF ID M021841

This sequence of lessons explores the geometry of similar triangles using two real world objects: ironing boards and pantographs. In the first lesson, students investigate different ironing board leg lengths and pivot positions using similar and congruent triangles. In the second lesson, they use their knowledge of parallelogram properties and similar triangles to explore and explain how pantographs work. Each lesson is outlined in detail including curriculum links, materials needed, sample answers, discussion points and student resources such as links for simulations online. This sequence is part of the reSolve: Maths by Inquiry special topic 'Mechanical Linkages and Deductive Geometry'.

Educational details

Educational value
  • This resource is extremely valuable for the year 9 mathematics content descriptions about similar triangles. Students investigate similar triangles and associated angle properties using real world objects and computer simulations.
  • The resource is also valuable for supporting the Numeracy general capability. The lesson provides multiple opportunities for students to visualise, describe and apply their understanding of the features and properties of 2D shapes.
  • The resource is also of value for supporting the Information and Communication Technology general capability as students use simulations and digital models to generate data and information to support their understanding of similar triangles.
Year level


Other details

  • Contributor
  • Name: Education Services Australia
  • Organization: Education Services Australia
  • Description: Data manager
  • Address: VIC, AUSTRALIA
  • URL: http://www.esa.edu.au/
  • Copyright Holder
  • Name: Australian Government Department of Education and Training
  • Organization: Australian Government Department of Education and Training
  • Publisher
  • Name: Australian Academy of Science
  • Organization: Australian Academy of Science
  • Description: Publisher
  • URL: https://www.science.org.au/
  • Resource metadata contributed by
  • Name: Education Services Australia Ltd
  • Organisation: Education Services Australia Ltd
  • Address: AUSTRALIA
  • URL: www.esa.edu.au
Access profile
  • Unknown
Learning Resource Type
  • Online
  • © Australian Government Department of Education and Training 2018. Unless otherwise indicated, this material may be used in accordance with the Creative Commons Attribution 4.0 International (CC BY 4.0) licence.