Final answer:
The southern and northern delegates at the Constitutional Convention agreed to the Three-Fifths Compromise, which determined the counting of slaves for congressional representation.
Step-by-step explanation:
The compromise that the southern and northern delegates agreed to during the Constitutional Convention was the Three-Fifths Compromise. This compromise settled the debate over the counting of slaves for congressional representation. Under the Three-Fifths Compromise, each slave would be counted as three-fifths of a person for both determining representation and taxation purposes.