Ind. Code § 5-1.2-3-4

Sec. 4. The powers of the authority are vested in the members. Three (3) members of the authority constitute a quorum for the transaction of business. The affirmative vote of at least three (3) members is necessary for any action to be taken by the authority. Members may vote by written proxy delivered in advance to any other member who is present at the meeting. A vacancy in the membership of the authority does not impair the right of a quorum to exercise all rights and perform all duties of the authority.