Year 9, Unit 2 – working with triangles
The lessons and sequence in this unit are designed to allow students to use the properties of right-angled triangles to solve a range of geometrical, measurement and real world problems.
This program of learning addresses content from the focus areas Trigonometry A, Linear relationships A, Numbers of any magnitude, as well as Path focus areas Linear relationships C, and Indices C.
The Mathematics K–10 syllabus (2023) is to be taught in Years 3 to 10 from 2024.
Detailed implementation information including key features and resources is available on the Mathematics syllabus development page (NESA).
Working with triangles is a 16-lesson unit for Year 9 with resources.
Introduction
Working with triangles (DOCX 162 KB)
Lesson 1 – 45-degree angles
Lesson 2 – larger and smaller angles
Lesson 3 – the tangent ratio
Lesson 4 – the sine and cosine ratios
Lesson 5 – I lost my calculator
I lost my calculator (DOCX 102 KB)
Lesson 6 – finding missing sides
Lesson 7 – significant distances
Lesson 8 – mapping the classroom
Mapping the classroom (DOCX 7.1 MB)
Lesson 9 – surd is the word
Surd is the word (DOCX 125 KB)
Lesson 10 – distances
Lesson 11 – midpoints
Lesson 12 – trigonometry for navigation
Trigonometry for navigation (DOCX 1.2 MB)
Lesson 13 – how far around is one degree?
Lesson 14 – how steep is too steep?
Lesson 15 – slopes as gradients
Slopes as gradients (DOCX 1.9 MB)
Lesson 16 – gradients in the Cartesian plane
Syllabus outcomes and content descriptors from Mathematics K–10 Syllabus © NSW Education Standards Authority (NESA) for and on behalf of the Crown in right of the State of New South Wales, 2023.