The Missouri compromise was all about keeping the balance of power in the senate in north and south . Maine added to free states, Missouri added to slaveholders the compromise of 1850 also kept the balance of powers but introduced the fugitive slave law and popular sovereignty.
Answer: The Missouri Compromise kept the balance by admitting Missouri as a slave state, admitting Maine as a free state, and creating a 36°30' line making all Land north of the line slavery free