Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 2 - No. 3)
In finding lengths and angles in 3 dimensions, which of the following is the most useful?
Complex numbers
Right-angled triangles
Isosceles triangles
Spheres
คำอธิบาย
Right-angled triangles are essential when dealing with three-dimensional geometry.