trigonometry
posted by eekim on .
a man measured the angle of elevation of the top of a tower to be 70 degree. When he walked 300 m. further, the angle of elevation of the top was 35 degree. What is the height of the tower?

make a diagram
label the tower AB , where A is the top of the tower.
label the man's first position C, his second position D
so that DC = 300
Look at triangle ADC,
angle D = 35°
angle ACD = 110° , so then
angle DAC = 35°
so the triangle is isosceles (lucky) and AC = 300
Then in the rightangled triangle ACB ,
sin70 = AB/300
AB = 300sin70 = 281.9 m
(had the triangle not been isosceles, I would have used the Sine Law to find AC ) 
A BOY OBSERVED THAT THE ANGLE OF ELEVATION OF THE TOP OF A TOWER IS 32 Degree HE THEN WALKS 8m Towards The Tower And THEN DISCOVER THAT THE OF Angle Of Elevation Is 43degree .Find The Height Of The Tower