Show that the relation R, defined by 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, 1 3 and T_3 with sides 6, 8, 10.