Teacher guide reSolve: Trigonometry: Rule of Twelfths

TLF ID M021847

This sequence of three lessons gives students the opportunity to explore how tidal variations can be modelled and predicted using trigonometric functions and approximated with useful 'rules of thumb'. Students use real tidal data to explore how sailors make predictions at sea, draw their own graphs using a range of approximation methods including segments of sine curves and then make comparisons between these methods. The lessons are outlined in detail including curriculum links, materials needed, discussion points and student resources such as links to real data and modelling tools. This sequence is part of the reSolve: Maths by Inquiry program.

Educational details

Educational value
  • This resource is valuable for supporting the Statistics and Probability strand of Year 10A mathematics. It relates to the content description about using the unit circle to define and graph trigonometric functions. There are various activities during the lesson where students are asked to use trignometric functions in modelling tidal variations.
  • The resource is also valuable for supporting the general capabilities of Numeracy and Information and Communication Technologies. The lessons provide authentic opportunities for students to apply their understanding of patterns and relationships when solving problems in authentic contexts and use ICT to perform calculations, draw graphs, interpret data and investigate and model concepts and relationships.
Year level


Learning area
  • Mathematics

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.