The angle of elevation of the top of a light house, as seen by a pers

1.	The angle of elevation of the top of a light house, as seen by a person onthe ground such that tan =5/12When the person moves a distance of 240 m towards the lighthouse, the angle of elevation becomes phi such that tan phi=3/4-Find the height of the lighthouse.
Answer» AB =height of the lighthouse AB/BD = 5/12 = h/240+ x 5(240+x) = 12h 1200+ 5x = 12 h (1) AB/BC = h/x 3x = 4h 3x/4 =h 1200+ 5x = 1(3x/4) 1200+5x = 9x 1200 = 4x 1200/4 = x 300 = x h = 3(300)/4 = 900/4 = 225mHence height is 225m

The angle of elevation of the top of a light house, as seen by a person onthe ground such that tan =5/12When the person moves a distance of 240 m towards the lighthouse, the angle of elevation becomes phi such that tan phi=3/4-Find the height of the lighthouse.

Answer»

AB =height of the lighthouse

AB/BD = 5/12 = h/240+ x

5(240+x) = 12h

1200+ 5x = 12 h (1)

AB/BC = h/x

3x = 4h

3x/4 =h

1200+ 5x = 1(3x/4)

1200+5x = 9x

1200 = 4x

1200/4 = x

300 = x

h = 3(300)/4 = 900/4 = 225mHence height is 225m