The general rule is that where the law relating to a particular subject does not specify the vote required to do a particular act, a majority vote is sufficient. This rule does not necessarily mean that a majority of the body must vote to pass the measure. In State ex rel. Burdick v. Tyrell, 158 Wis. 425, 149 N.W. 280 (1914), the Wisconsin Supreme Court held that where the law does not specify that a majority of the members of the body must vote, a vote by a majority of the quorum is sufficient.
In State ex rel. Burdick, the common council consisted of six alderpersons and the mayor, so a quorum of the council was four. The whole council was present for a vote to fill a council vacancy but only four votes were cast. Three alderpersons voted for one candidate, and one alderperson cast a blank ballot. The court held that the vote was sufficient because a majority of the quorum had voted in favor of a particular candidate.
Sometimes statutes require a super-majority vote (two-thirds, three-fourths, etc.) to pass a measure. If a required super-majority vote results in a certain number of whole votes and a fraction, the fraction must be counted as a whole vote even though this results in an even higher percentage of votes by the body to approve than would be the case if the body were equally divisible by the super-majority fraction denominator. For example, if a body has eight members and a measure requires a two-thirds vote of all members for passage, then passage requires six votes since two-thirds of eight is 5.333 which must be rounded up to six. See 4 McQuillin, Municipal Corporations sec. 13.39 (3rd ed.); League opinion Governing Bodies 321.