To see if two figures are similar, the first ting you look for is to see if they have the same general shape. Figures are mathematically similar if all corresponding angles are congruent. The two images that you are trying to see are similar must also be related by a scale factor. These are two ways that you can see if an image is similar to another one. Another way you can check is by using ratios. You can use true proportions to see if two images are similar.

Any two rectangles are similar

False. Although all corresponding angles are congruent, the sides are different lengths. Not all rectangles can be related by a scale factor, which means they are not similar.

Any two equilateral triangles are similar

True. All corresponding angles are congruent. When the angles are congruent, they are automatically similar.