Question

∠1=∠2,AE垂直OB于E,BO垂直OA于D,交点为C,求证：AC＝BC

Answer 1

∵角1=∠2,∵∠OEC=∠ODC,OC=OC ∴△ODC全等于△OEC∴DC=CE,

再∵∠CDA=∠CEB,DC=CE,∠DCA=∠ECB∴△ADC全等于△ECB（ASA)∴AC=BC