In the diagram, BC (30) is an altitude of ABD. What is the length of CD? (AC=16)?

as I have no diagram to consider all I can state is that from the given information the length of AD can be anything { ≥ 16}...I do ume that ABD describes a triangle...for consider the line from A to D , C is on this line, and as we move on this line past C any of the points could be D and meet the conditions given