Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 4 - No. 49)
If the angle of depression from a point A to a point B is 30 degrees, what is the angle of elevation from B to A (assuming they are at different elevations and the ground is flat)?
30 degrees
60 degrees
150 degrees
Cannot be determined
คำอธิบาย
The angle of elevation and the angle of depression are equal (alternate interior angles).