Answer: Three-Fourths or ¾
Step-by-step explanation:
According to Article V of the Constitution, in other to amend the Constitution, two methods may be used; the Congressional Proposal and the Convention Method.
The Congressional Method is the more popular one and requires that ⅔ of both Chambers of Congress propose the amendment.
The Second being the Convention Method, ⅔ of states ask Congress to organise a convention and the amendment is then proposed here. It has never been used though.
The common factor between both these methods is that for the Amendment to be passed, it needs to be Ratified by THREE-FOURTHS of state conventions or state legislatures, the decision of which to choose, is up to Congress.