根据正弦定理：sinA/sinB=sinB/sinC=sinC/sinA∴sinAsinC=sin² B①,sinAsinB=sin²C②,sinBsinC=sin² A①/②：sinC/sinB=sin² B/sin² C∴sinB/sinC=1∵∠B+∠C＜180°∴∠B=∠C同理,∠A=∠B...