Calculating Crane Height from Angles

[Cbray]

To calculate the height of a crane which is on top of a building, dennis measures the angle of elevation to the bottom and the top of the crane. these were 62 degrees and 68 degrees respectively. if the building is 42 metres high find the height of the crane.

I'm asking for a friend, excuse the English it was sent through an instant message.
He would prefer the answer (and working if possible), thanks! :)

 

[ashishsinghal]

Just give it a try and we will guide you through. Start with making a rough diagram.