The shadow of a building when the angle of elevation of the sun is 45 degree is found to be 10m longer than when it was 60 degree. Find the height of the building .

look at the diagram and solve as follows

tan45=AB/n+10

⇒1=AB/n+10

⇒AB=n+10  ...... (1)

tan60=AB/n

AB=n√3  ...... (2)

solving (1) and (2) we get

n = 13.69

therefore AB = 23.7 approx