For shapes to be considered similar, what aspect must remain constant?

For shapes to be considered similar, all corresponding angles must be the same. Similar shapes maintain their proportional relationship in terms of shape, which means that while their sizes may differ, their angles remain consistent across the figures. This constant angle relationship confirms that the shapes retain the same form, which is a defining characteristic of similarity.

Having the same area is not a requirement for similarity, as two shapes can have the same angles but vary greatly in size. Color differences are irrelevant to similarity and do not impact the geometric properties of the shapes. Furthermore, the notion that sides must have different ratios contradicts the definition of similarity; rather, similar shapes will have sides that are in proportion to each other, maintaining consistent ratios, not differing ones. This reinforces the key concept that similarity is defined by equal angles and proportional sides.