∵∠A=58°，∴∠ABC+∠ACB=180°-∠A=180°-58°=122°…①，∵BH是∠ABC的平分线，∴∠HBC=12∠ABC，∵∠ACD是△ABC的外角，CH是外角∠ACD的角平分线，∴∠ACH=12（∠A+∠ABC），∴∠BCH=∠ACB+∠ACH=∠ACB+12（∠...