Year 10 Mathematics – Term 2 (WA Curriculum): Trigonometry, Similarity and 3D Geometry

What this unit covers

In Term 2, Year 10 Mathematics in the WA Curriculum centres on the unit “Trigonometry, Similarity and 3D Geometry”.

Students will explore angles of elevation and depression, investigate similar triangles and scaling effects, calculate volumes of composite solids, and apply measurement accuracy in real-world contexts.

Lesson sequence (30 lessons)

The unit breaks down into the following lesson-by-lesson sequence — each title below is a teachable lesson, in order:

1. Identifying and defining angles of elevation in real-world contexts
2. Identifying and defining angles of depression from observation points
3. Drawing and labeling right-angled triangles with elevation and depression angles
4. Selecting appropriate trigonometric ratios for elevation problems
5. Calculating unknown sides using angles of elevation
6. Calculating unknown angles using trigonometric ratios in depression scenarios
7. Solving multi-step problems involving angles of elevation and depression
8. Constructing pairs of triangles with given side lengths manually
9. Using dynamic geometry software to create similar triangles
10. Comparing corresponding sides and angles in similar triangles
11. Proving triangle similarity using side ratios and angle measures
12. Explaining reasoning for triangle similarity in written form
13. Investigating scale factors between similar triangles
14. Predicting perimeter changes when shapes are enlarged
15. Calculating actual perimeters of enlarged triangles and quadrilaterals
16. Investigating area changes when shapes are scaled up or down
17. Determining area relationships in similar circles and composite figures
18. Comparing predicted and actual measurements in scaling investigations
19. Identifying base ends and heights in composite prisms
20. Calculating cross-sectional areas of irregular prism bases
21. Determining volumes by multiplying base area and height
22. Finding volumes of composite solids using decomposition strategies
23. Measuring angles of elevation using clinometers and protractors
24. Calculating distances using trigonometry and comparing with actual measurements
25. Analyzing sources of error in practical measurement activities
26. Discussing accuracy of results in terms of measurement limitations
27. Constructing similar 3D objects using various materials and software
28. Calculating surface areas of original and scaled 3D objects
29. Investigating volume relationships in enlarged and reduced objects
30. Solving real-world problems involving drone observations and angle measurements

Curriculum codes in this unit

Content codes:

Reading the codes: WA codes (the ones starting with WA) pack the year level, learning area, strand and content number into one string, while the national Australian Curriculum v9 uses a different anatomy that starts with AC9 — same content family, different labels. Our complete WA Curriculum guide decodes both, character by character.

Planning notes for Term 2

WA terms run roughly 9–11 weeks, and in 2026 Term 2 runs from Monday 20 April to Friday 3 July — 11 weeks for WA public schools. With 30 lessons in this unit, that leaves breathing room for assessment, moderation and the weeks that disappear to carnivals, camps and public holidays — plan the assessable work to land two to three weeks before the end of term rather than in the final week.