## Cube Face Diagonal

A cube with a side (S) of 20 has a maximum face diagonal length (L) of 28.2843.

## Cube Face Diagonal Formula

find the maximum face diagonal Length for cubes with a side length S

- L = S√2

substitute the side length S with the measured value, in this example lets use a side length of 4

- L = 4√2

now use the square root function on your calculator to find the square root of 2, then multiply this by the side length of 4.

**L = 5.6569**

The longest diagonal line across the face of a cube with side length (S) can be determined by dividing the Side by √2.