# similar

Similar, in mathematics, is having the same shape but not necessarily the same size (see congruent).
Two triangles are similar if they have
equal angles and their corresponding sides, say, *a*_{1}, *b*_{1}, *c*_{1} and *a*_{2}, *b*_{2}, *c*_{2}, have a common ratio, *r *: *a*_{1}/*a*_{2} = *b*_{1}/*b*_{2} = *c*_{1}/*c*_{2}. In general, a **similarity** is a transformation under which the
distance between any corresponding pair of points changes by the same factor.