1、題型突破（三）圓中的有關(guān)計(jì)算,圓中有關(guān)計(jì)算,一般情況下在中考題中所占的分值為5分,難度中等略偏上,對(duì)大多數(shù)考生來(lái)說(shuō)得分率為60%左右,所考查知識(shí)點(diǎn)相對(duì)穩(wěn)定,主要考查切線的性質(zhì)、勾股定理、垂徑定理、銳角三角函數(shù)、等腰三角形的性質(zhì)、相似等知識(shí). 解題的關(guān)鍵是學(xué)會(huì)添加常用輔助線,靈活運(yùn)用所學(xué)知識(shí)解決問題.從題目構(gòu)造來(lái)看,通常有兩問.學(xué)生往往對(duì)第二問顯得力不從心,若是計(jì)算類的則在構(gòu)建等量關(guān)系時(shí)缺失頭緒,通常需要添加適當(dāng)?shù)妮o助線,通過建立方程模型,建立已知與未知的聯(lián)系(一般情況下,應(yīng)把所求的線段直接或間接地放入可解的直角三角形中.然后利用勾股定理、相似、三角函數(shù)等計(jì)算相應(yīng)線段長(zhǎng)度).,類型1運(yùn)用勾股定理

2、、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,類型1

3、運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24

4、題）,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,圖Z3-9,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,圖Z3-9,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,圖Z3-10,類型1運(yùn)用勾股定理、三角函數(shù)計(jì)算線段長(zhǎng)度（針對(duì)2018 21題,2017 24題,2015 24題）,圖Z3-10,類型2運(yùn)用相似計(jì)算線段長(zhǎng)度,圖Z3-11,類型2運(yùn)用相似計(jì)算線段長(zhǎng)度,圖Z3-11,類型2運(yùn)用相似計(jì)算線段長(zhǎng)度,類型2運(yùn)用相似計(jì)算線段長(zhǎng)度