Question

Circle A has a radius of 2 inches, and circle B has a radius of 5 inches. Prove that the two circles are similar.

Answer 1

Wouldn't by definition ALL circles be similar?

Answer 2

Two circles are congruent if they have the same radius, regardless of where their centers are located. For
example, all circles of radius of 2 centimeters are congruent to each other. Similarly, all circles with a radius
of  254 miles are congruent to each other. If circles are not congruent, then they are similar with the similarity ratio given by the ratio of their radius. so for your case they are similiar but with a ratio of 2:5