I'm sorry there was a delay in getting back to you on this matter.
The law in California (the CA Corporations Code Section 1001) states that "A corporation may sell....all or substantially all of its assets when the principal terms are approved by the board, an, unless the transaction is in the usual and regular course of its business
, approved by the outstanding shares."
If the sale of real estate is not in the usual and regular course of business of the company, then the shareholders
of the corporation (which in this case is all three of you) means that it must only be approved by "the affirmative vote of a majority of the outstanding share entitled to vote." CCC Sec. 152.
In this case, since you do not have an operating agreement, I would assume that you all have an equal 33.3% share of the corporation and thus, it only takes the approval of two of you and you do not have to obtain the approval of the third person.
How much of the corporation's assets are tied up in the land?