Scale drawings of landmark towers

A \(900\) m tower is represented by a height of \(4.5\) cm on a scale drawing.

1. Find the scale in the form \(1:n\).[2]
2. Find the drawing height of a \(620\) m tower.[2]
3. A third tower is \(4.0\) cm high on the original drawing. Find its height on another drawing of scale \(1:50000\).[2]