1×4

1×4 is a notation that can refer to different concepts depending on the context. In mathematics, it describes a rectangle with sides of length 1 and 4 units. The area of such a rectangle is 4 square units, and its perimeter is 2(1+4) = 10 units. The diagonal length is sqrt(1^2 + 4^2) = sqrt(17), approximately 4.12 units.

In geometry and practical applications, a 1×4 rectangle is used to illustrate simple proportional relationships and can serve as a basic cross-section in problems involving area, perimeter, and similarity.

In carpentry and lumber, 1×4 refers to a common nominal board size. It is widely used for trim, furring, shelving, and light framing. The nominal dimension 1×4 does not reflect the actual finished size; typical actual cross-section is about 3/4 inch by 3 1/2 inches (19 mm by 89 mm). The length of boards varies by project and stock availability. Finished boards may be planed or rough-sawn, which can affect their exact dimensions.

When planning projects, it is important to distinguish nominal sizes from actual dimensions. For precise material calculations, use the actual cross-section (for a 1×4, roughly 3/4" × 3 1/2") and account for kerf loss from cutting. The term 1×4 can thus refer to both a simple geometric rectangle and a common construction plank, depending on the context.