A man wishes to estimate the distance of a nearby tower from him. He stands at a point A in front of the tower C and spots a very distant object in line with AC. He then walks perpendicular to AC up to B, a distance of 100 m, and looks at O and C again. Since O is very distant, the direction BO is practically the same as AO, but he finds the line of sight of C shifted from the original line of sight by an angle = `40^@` (`theta ` is known as 'parallax') estimate the distance of the tower C from his original position A.

Explanation

Parallax angle `theta= 40^(@), AB= AC tan theta`
`AC= AB//tan theta= 100m//tan40^(@)`
`=100m//0.8391= 119m`