:: deftheorem Def4 defines the_radius_of_the_circumcircle EUCLID12:def 6 :
for A, B, C being Point of (TOP-REAL 2) st A,B,C is_a_triangle holds
the_radius_of_the_circumcircle (A,B,C) = |.((the_circumcenter (A,B,C)) - A).|;