On the date set for hearing under RCW
57.24.170, residents or property owners of the area included in the resolution for annexation shall be afforded an opportunity to be heard. The board of commissioners may provide by resolution for annexation of the territory described in the resolution, but the effective date of the resolution shall be not less than forty-five days after the passage thereof. The board of commissioners shall cause notice of the proposed effective date of the annexation, together with a description of the property to be annexed, to be published at least once each week for two weeks subsequent to passage of the resolution, in one or more newspapers of general circulation within the district and in one or more newspapers of general circulation within the area to be annexed. Upon the filing of a timely and sufficient referendum petition under RCW
57.24.190, a referendum election shall be held under RCW
57.24.190, and the annexation shall be deemed approved by the voters unless a majority of the votes cast on the proposition are in opposition thereto. After the expiration of the forty-fifth day from but excluding the date of passage of the annexation resolution, if no timely and sufficient referendum petition has been filed, under RCW
57.24.190, the area annexed shall become a part of the district upon the date fixed in the resolution of annexation.