The tallest tower in a city is 100 metre high and a multistoried hotel at the City Centre is 20 m high. The angle of elevation of the top of a tower at the top of the hotel is 30 degree. A building 'h' metre high is situated on road connecting the tower with the City Centre at the distance of 1 km from the Tower. find the value of h if the top of the tower , building and the hotels are in the same straight line.