NDA2022MathematicsHeights and DistancesActual
A vertical tower stands on a horizontal plane and is surmounted by a vertical flagstaff of height h . At a point on the plane the angles of elevation of the bottom and top of the flagstaff are and 2 respectively. What is the height of the tower?
Options
- Ah
- Bh
- Ch 2
- Dh 2
Correct answer
C. h 2
Step-by-step solution
In PBC = B C P C P C=B C ...(i) In P A C aligned & 2 = h+B C P C & P C 2 =h+B C aligned aligned & B C 2 1- ^2 =h+B C & 2 B C 1- ^2 -B C=h & 1+ ^2 1- ^2 B C=h & B C= 1- ^2 1+ ^2 h= 2 h aligned