What does it mean for two shapes to be similar?

For two shapes to be considered similar, they must have the same shape but different sizes. This means that all corresponding angles in the shapes are equal, while the lengths of corresponding sides are proportional rather than equal. When two shapes are similar, one can be thought of as a scaled version of the other, which allows for variations in size while maintaining congruence in angle measures. This property is fundamental to understanding similarity in geometry and is often demonstrated through the use of scale factors when relating the dimensions of the two shapes.