Show that the R defined on the set A of all triangles as $R = \{(T_1, T_2): T_1$ is similar to $T_2 \}$ is an equivalence relation. Consider three right-angled triangles \( T_1\) with sides 3, 4, 5, \( T_2\) with sides 5, 12, 13 and \( T_3\) with sides 6, 8, 10. Which triangles among \( T_1, T_2 and T_3\) are related?