Was the three-fifths compromise necessary to achieve ratification of the constitution?
The South and the North had to find a compromise
The constitution could not be ratified if nine out of the thirteen colonies did not ratify it and since the number of seats per each state was to be determined by the population thus they decided that slaves would be counted as three-fifths of a real citizen and yet it was absurd since the latter could not vote.The Three-Fifths Compromise was proposed by James Wilson and Roger Sherman, who were both delegates for the Constitutional Convention of 1787.
The constitution was ratified only in 1789. More information:https://constitution.laws.com/three-fifths-compromise