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Breaking Down 3D
Breaking Down 3D
3D problems look scary, but here's the secret: they're just 2D problems in disguise! Every 3D trig question can be solved by finding right-angled triangles hidden within the 3D shape. Draw them out flat, and suddenly it's just regular SOHCAHTOA or Pythagoras!
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Exam Tips
X Using 3D thinking directly
Always extract 2D triangles from the 3D shape
Every 3D problem becomes a series of 2D problems
X Forgetting to use the base diagonal
Often need to find the base diagonal FIRST
The base diagonal is usually the key stepping stone
Now try it yourself
Quiz · Question 1 of 12
To find the angle between a line and a horizontal plane in a 3D problem, which technique is typically used?
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This topic in real past papers
Every real exam question we've found on 3d trigonometry, with a full worked answer.
AQA Paper 3
Two of the four sittings we have full papers for embed a right-angled triangle inside a 3D solid and require trigonometry, sometimes with Pythagoras' theorem too, to find a length or a volume.
Edexcel Paper 2
All three sittings we have full papers for test trigonometry to find a missing length or angle, and June 2019 tests it twice: once in a simple right-angled triangle and once inside a 3D solid.