How do you convert cubic feet to board feet for a rectangular piece of lumber?

To convert cubic feet to board feet for a rectangular piece of lumber, the correct approach is to divide the volume in cubic feet by 12. This is because one board foot is defined as a volume of 1 inch thick by 12 inches wide by 12 inches long. Therefore, there are 144 cubic inches in a board foot. Since there are 12 inches in a foot, a board foot effectively represents a volume of 144 cubic inches.

Given this understanding, when you have a volume in cubic feet, you can find how many board feet this translates into by recognizing that 1 cubic foot equals 1,728 cubic inches (since there are 12 inches in a foot: 12 x 12 x 12 = 1,728). To find the number of board feet, you take the total cubic inches and divide it by the number of cubic inches in a board foot (144). If converted to feet, this process simplifies to dividing the cubic feet by 12.

This makes the division by 12 necessary to reach the equivalent measurement in board feet, making it the correct method for this conversion.