Congruent shapes are shapes that are exactly the same. The corresponding sides are the same and the corresponding angles are the same.

Two shapes are said to be similar if they are exactly the same shape, but are different in size. All sides are in the same proportion defined by the scale factor.

If 2 shapes are similar and the scale factor of the lengths is x, then the scale factor of the area is x2 and the scale factor iof the volume is x3