1.
(1) ç¸ç.
å 为AOB=COD=90 AOB+BOD=COD+BOD
åç±äº AOB+BOD=AOD COD+BOD=BOC
æ以AOD=BOC
(2). AOC+BOD=180
å 为以O为顶ç¹çå个è§AOB, BOD, COD, AOCçå为360度,
AOB=COD=90, ä»èAOB+COD=180度, å©ä¸ä¸¤ä¸ªè§çåå°±æ¯180
2.
(1)ç¸ç.
å 为
AOD=AOB- BOD=90-BOD
BOC=COD-BOD=90- BOD
æ以AOD=BOC
(2)æç«
å 为
AOD+BOD=90 BOC+BOD=90
AOD+BOD+BOC+BOD=180
èAOC=AOD+BOD+BOC
æ以AOC+BOD=180
å¸æ对æ¨æ帮å©,è¥æä¸æç½çå°æ¹,å¯ä»¥è¿½é®, 谢谢
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