# How old is the (Pythagorean) theorem?

This is an introductory lesson in a series of lessons on Pythagoras theorem. Students learn about Pythagoras’ theorem and its application in calculating lengths in right-angled triangles. They explore the statement of the theorem, some of its history, a simple geometric proof and visual demonstrations of the theorem. Students apply the theorem to the two types of problem calculating the length of the third side of a right-angled triangle, given the lengths of the other two sides.

Year level(s) Year 8
Audience Teacher
Purpose Teaching resource
Format Web page
Teaching strategies and pedagogical approaches Mathematics investigation, Questioning, Explicit teaching, Concrete Representational Abstract model, Worked examples
Keywords problem solving, right-angled triangles, triangles, Maths Hub lesson plan

## Curriculum alignment

Curriculum connections Critical and creative thinking
Strand and focus Number, Measurement
Topics Pythagoras and trigonometry
AC: Mathematics (V9.0) content descriptions
AC9M8N01

Recognise irrational numbers in applied contexts, including square roots and Π

AC9M8M06

Use Pythagoras' theorem to solve problems involving the side lengths of right-angled triangles

Numeracy progression Understanding geometric properties (P7)
Understanding units of measurement (P10)
Multiplicative strategies (P9)