Now. 3D shapes, they have 3 dimensions. Length, width and depth. What would the 3D version of a square be? A cube. A cube has 6 square faces which are all the same size. Whereas cuboids ...

For example a pentagon is always a shape that has 5 sides. An equilateral triangle has 3 sides of equal length. The dashes on the lines show they are equal in length. All of the angles are also equal.