2013 · Q95
A spherical balloon of radius r subtends 60° at the observer's eye. Angle of elevation of centre is 60°; h = height of centre. Which is correct?
Elementary MathematicsTrigonometry
- Ah=r
- Bh=√2 r
- Ch=√3 r
- Dh=2r
Explanation
sin30=r/d, sin60=h/d → h=√3 r. Answer C.