如圖,四邊形內(nèi)接于⊙O,
是⊙O的直徑,
,垂足為
,
平分
.
(1)求證:是⊙O的切線;
(2)若,求
的長.
解:(1)證明:連接,
平分
,
.
.
.
.························································································ 3分
,
.
.
是
的切線.····································· 5分
(2)是直徑,
.
,
.··················································································· 6分
平分
,
.
.········································································ 8分
在中,
.
在中,
.
的長是1cm,
的長是4cm.························································ 10分
【解析】略
科目:初中數(shù)學(xué) 來源:2011年廣東省深圳市南山區(qū)初二期末數(shù)學(xué)卷 題型:解答題
如圖,四邊形內(nèi)接于⊙O,
是⊙O的直徑,
,垂足為
,
平分
.
(1)求證:是⊙O的切線;
(2)若,求
的長.
查看答案和解析>>
科目:初中數(shù)學(xué) 來源:2011年廣東省深圳市南山區(qū)初二期末數(shù)學(xué)卷 題型:解答題
如圖,四邊形內(nèi)接于⊙O,
是⊙O的直徑,
,垂足為
,
平分
.
(1)求證:是⊙O的切線;
(2)若,求
的長.
查看答案和解析>>
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