Trigonometry and Boat Speed

A boat is at \(C\), \(150\) m away from the foot of cliff at \(B\).

1. The angle of elevation of the top of the cliff \(A\) from the boat is \(23{}^\circ\).
   Find the height of the cliff.
2. If the boat moved \(50\) m from \(C\) towards the cliff at \(D\), find the angle of elevation from the boat to the top of the cliff.
3. If the boat moved from \(C\) to the foot of the cliff \(B\) in \(2\) minutes, find the speed of the boat in km/h.