A room has dimensions of 12' by 13' by 8'. Calculate the amount of molding necessary for a decorative strip at the floor and at the ceiling.

The dimensions of a room are determined by its length, width and height. In this problem we will assign a length of 12', a width of 13', and a height of 8' (as standard ceiling heights in most homes are 8' high). To calculate the amount of molding needed for strips at the top of the room and the bottom of the room we need to find the perimeter of the room. A length of 12' and a width of 13' make this room a rectangle. Determine the perimeter by adding 12' + 13' and multiplying the sum by 2 to get 50'. Multiply 50' x 2 to account for a decorative strip of molding at the floor and the ceiling and you get 100' total molding needed.