**In Euclidean geometry, two objects are similar if they have the same shape, or one has the same shape as the mirror image of the other. More precisely, one can be obtained from the other by uniformly scaling, possibly with additional translation, rotation and reflection. Two triangles are said to be similar if their corresponding angles are equal and corresponding sides are proportional. By using AAA similarity theorem, SSS similarity theorem and SAS similarity theorem, we can prove two triangles are similar. When we are comparing two things — physical objects, ideas, or experiences — you often look at their similarities and their differences. Difference is the opposite of similarity. Both squares and rectangles have four sides that is a similarity between them.The similarity is an idea in geometry. It means that two polygons, line segments, or other figures have the same shape. Similar objects do not need to have the same size. Two shapes are similar if their angles have the same measure, and their sides are proportional. The concept of similarity extends to polygons with more than three sides. Given any two similar polygons, corresponding sides were taken in the same sequence (even if clockwise for one polygon and counter-clockwise for the other) are proportional and corresponding angles taken in the same sequence are equal in measure. **