The diagonal of a cube is 20 cm . Identify the length of an
edge. Round to the nearest tenth, if necessary.
13.8 cm
20 cm
14.1 cm
11.5 cm
Of 12

To find the length of an edge of a cube when you know the diagonal, you can use the formula for the diagonal of a cube, which is , where is the edge length. Given that the diagonal is 20 cm, you can rearrange the formula to solve for :

So, the length of the edge is 11.5 cm!

Did you know that the properties of a cube make it unique in geometry? All its angles are right angles, and all its edges are of equal length. This symmetry and regularity is why cubes are often used in design and architecture to produce aesthetically pleasing and structurally sound shapes.

If you’re working with cubes or similar geometric problems frequently, try to remember key relationships like the diagonal formula! A common mistake is to confuse the diagonal of a cube with that of a square. It’s vital to keep the dimensions in mind since cubes are three-dimensional, while squares are only two-dimensional! Always visualize the shape to avoid these mix-ups.