Answer:
To approve an amendment to the US constitution, two-thirds of members of Congress must vote in favor of it
Step-by-step explanation:
Article V of the U.S. Constitution provides two ways in which the U.S. Constitution can be amendment: the first one enables Congress to start the process, while the second enables state legislatures to start it. When Congress starts the process, both houses have to propose an amendment with at least two-thirds of votes in favor each. If the proposal reaches that majority of votes, then it has to be voted on by the state legislatures OR the state conventions. Lastly, only if the amendment is approved by at least three-fourths of the state legislatures or the state convention, it becomes a law.