If there is a protest against any change signed by the owners of twenty percent (20%) or more of the area of the lots included in the proposed change, or of those immediately adjacent within a distance of one hundred forty feet (140'), the amendment shall not become effective except upon the affirmative vote of three-fourths (3/4) of all the members of the city council. In determining the one hundred forty feet (140'), the width of any intervening street or alley shall not be included. The provisions for public hearings and notice apply to all changes or amendments. (1960 Compilation § 26-115; amd. Ord. 86-5; Ord. 87-3)