Right-Angled Triangles
Pythagoras' theorem, the trigonometric ratios, finding unknown sides and angles, elevation and depression, and bearings.
Active lessons
9
Status
Active
Lesson flow
Learn -> Guided Practice -> Independent Practice -> Mastery Quiz
How to use this unit
- Start from lesson 1 and move through the pathway in order.
- Use guided practice before attempting independent practice.
- Mastery quizzes check whether the skill is ready for review or extension.
Unit pathway
Lesson pathway
9 of 9 active
Lesson 1
4A Pythagoras' Theorem
Identify the hypotenuse and use a² + b² = c² to find it in a right-angled triangle.
Lesson 2
4B Applying Pythagoras
Find a shorter side and solve practical problems (ladders, ramps, diagonals) with Pythagoras.
Lesson 3
4C Trigonometric Ratios
Solve right-angle triangle problems using sine, cosine and tangent ratios.
Lesson 4
4D Using the Calculator
Evaluate trig ratios and use inverse trig to find an angle, with correct degree mode and rounding.
Lesson 5
4E Finding an Unknown Side
Use SOH-CAH-TOA to find an unknown side: identify the sides relative to the angle, choose the ratio, solve.
Lesson 6
4F Finding an Unknown Angle
Find an unknown angle from two known sides using inverse trigonometry.
Lesson 7
4G Solving Practical Problems
Apply sine, cosine and tangent to multi-step practical problems involving angles of elevation and depression, ramp gradients, and distances in real-world contexts.
Lesson 8
4H Angles of Elevation and Depression
Distinguish elevation and depression and use trig to find heights and distances.
Lesson 9
4I Compass and True Bearings
Convert between true bearings and compass bearings, find back bearings, and solve practical direction problems using right-angle trigonometry.
Part of the Online Learning Package
Unit previews stay public, while individual lessons require active online learning access.