题目内容
如图,已知□ABCD的对角线AC、BD相交于点O,AC =12,BD=18,且△AOB的周长l=23,求AB的长.
8
∵□ABCD的对角线AC、BD相交于点O,AC =12,BD=18,·········· 1分
∴ AO=AC=6,······························· 3分
BO=BD=9.································· 5分
又∵△AOB的周长l=23,∴ AB=l–(AO+BO)=23–(6+9)=8.············· 7分
根据平行四边形中两条对角线相互平分的性质可求解
∴ AO=AC=6,······························· 3分
BO=BD=9.································· 5分
又∵△AOB的周长l=23,∴ AB=l–(AO+BO)=23–(6+9)=8.············· 7分
根据平行四边形中两条对角线相互平分的性质可求解
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