<Li> The sum of the ratios on the three altitudes of the distance of the orthocenter from the vertex to the length of the altitude is 2: </Li> <Dl> <Dd> A H A D + B H B E + C H C F = 2 . (\ displaystyle (\ frac (AH) (AD)) + (\ frac (BH) (BE)) + (\ frac (CH) (CF)) = 2 .) </Dd> </Dl> <Dd> A H A D + B H B E + C H C F = 2 . (\ displaystyle (\ frac (AH) (AD)) + (\ frac (BH) (BE)) + (\ frac (CH) (CF)) = 2 .) </Dd> <Ul> <Li> The isogonal conjugate of the orthocenter is the circumcenter of the triangle . </Li> </Ul>

Which segment is an altitude for triangle abc