Lot area and width. Every lot shall have a lot area of not less than one acre and shall be not less than 125 feet at the building line, provided that where the lot does not front on a public road, the lot shall be connected to an improved public street or road by a right-of-way of a minimum width of 20 feet with a paved drive of a minimum width of 10 feet, which right-of-way shall be in addition to the lot area of one acre.