Final answer:
Two figures are called similar in geometry if they have the same shape but different sizes. Corresponding angles must be congruent, and the ratios of corresponding side lengths must be equal. An example of similarity is when two triangles have congruent angles and equal ratio of corresponding side lengths.
Step-by-step explanation:
In geometry, two figures are called similar if they have the same shape but different sizes. To be considered similar, the corresponding angles of the figures must be congruent, and the ratios of their corresponding side lengths must be equal.
For example, consider two triangles ABC and DEF. If angle A is congruent to angle D, angle B is congruent to angle E, and angle C is congruent to angle F, and the ratios of their side lengths AB/DE, BC/EF, and AC/DF are all equal, then the triangles are similar.
On the other hand, a counterexample for similarity would be if the angles of the figures are not congruent or if the ratios of their corresponding side lengths are not equal.