What group must approve changes to the state constitution

Amendments can be proposed in Congress when 2/3rd of both Houses agree. The states can play a role in proposing changes to the Constitution as well: 2/3 rds of the state legislatures must call Conventions to propose amendments. Whether amendments are first proposed by the states or Congress, 3/4 ths of the states must ratify (or approve) them before they become a part of the Constitution-the Supreme law of the land.