MA30-09 Maths Coming soon
Finding lengths in 3D using Pythagoras and trigonometry
MA30-09
This lesson is coming soon.
In this lesson
Combine Pythagoras' theorem and trigonometry across multiple steps to find a missing length inside a 3D solid, carrying exact or unrounded values between steps.
What it covers
- Identify a right-angled triangle inside a 3D solid where the given/wanted information mixes a known angle and known side (trigonometry), distinct from a triangle with two known sides (Pythagoras)
- Chain a Pythagoras step and a trigonometry step across two connected triangles within the same solid to find a single target length
- Carry an unrounded (exact or several-decimal-place) intermediate value through the chain rather than rounding after the first step
Key words
For: Cambridge IGCSE 0580, Edexcel IGCSE 4MA1
On the specification
| Board | Spec | Statement |
|---|---|---|
| Cambridge IGCSE 0580 | C6.6 | Extended content only. |
| Cambridge IGCSE 0580 | E6.6 | Carry out calculations and solve problems in three dimensions using Pythagoras' theorem and trigonometry, including calculating the angle between a line and a plane. |
| Edexcel IGCSE 4MA1 | H4.8F | Apply trigonometrical methods to solve problems in three dimensions, including finding the angle between a line and a plane |
For teachers
This GCSE Maths lesson teaches finding lengths in 3D using Pythagoras and trigonometry. By the end, students should be able to combine Pythagoras' theorem and trigonometry across multiple steps to find a missing length inside a 3D solid, carrying exact or unrounded values between steps. It works through two worked examples and the mistakes examiners report.