A board of county commissioners shall not approve a county renewal project for a county renewal area unless it has, by resolution, determined such area to be a slum area or a blighted area or a combination thereof and designated such area as appropriate for a county renewal project. The board shall not approve a county renewal plan until a general plan for the county has been prepared by the planning commission of the county. A board shall not acquire real property for a county renewal project unless it has approved the county renewal project in accordance with section 303.33 of the Revised Code.