26.3 解直角三角形 预学检验+课堂导学+同步练习（含答案）2023-2024学年冀教版数学九年级上册

第二十六章　解直角三角形 26.3 解直角三角形 INCLUDEPICTURE"复习回顾.tif" INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\复习回顾.tif" \* MERGEFORMATINET INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\复习回顾.tif" \* MERGEFORMATINET 1．如图，某游乐园彩虹滑梯的高度为h，滑梯的坡角为α，那么该彩虹滑梯的长度l为(　　) INCLUDEPICTURE"image3357.tif" INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\image3357.tif" \* MERGEFORMATINET INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\image3357.tif" \* MERGEFORMATINET (第1题)　 A. B．h·sin α C. D. 2．[2023烟台期中]如图，已知△ABC的三个顶点均在正方形网格的格点上，则下列结论错误的是(　　) INCLUDEPICTURE"image3363.tif" INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\image3363.tif" \* MERGEFORMATINET INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\image3363.tif" \* MERGEFORMATINET (第2题)　 A．cos C＝ B．tan B·tan C＝1 C．sin B＝sin C D．tan B＝ 3．在△ABC中，∠C＝90°，cos A＝，BC＝10，则AB＝_____． 4．如图，在Rt△ABC中，∠C＝90°，BC＝12，tan A＝，求AB的值． INCLUDEPICTURE"image3376.tif" INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\image3376.tif" \* MERGEFORMATINET INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\image3376.tif" \* MERGEFORMATINET INCLUDEPICTURE"预习效果检测.tif" INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\预习效果检测.tif" \* MERGEFORMATINET INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\预习效果检测.tif" \* MERGEFORMATINET 1．在直角三角形中，除直角外，还有_____和_____共五个元素．由这五个元素中的已知元素求出其余未知元素的过程，叫做解直角三角形． 2．如图，在Rt△ABC中，已知∠C＝90°，a＝4，c＝8，解这个直角三角形． INCLUDEPICTURE"image3379.tif" INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\image3379.tif" \* MERGEFORMATINET INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\image3379.tif" \* MERGEFORMATINET INCLUDEPICTURE"课堂导学.tif" INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\课堂导学.tif" \* MERGEFORMATINET INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\课堂导学.tif" \* MERGEFORMATINET INCLUDEPICTURE"W21.tif" INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\W21.tif" \* MERGEFORMATINET INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\W21.tif" \* MERGEFORMATINET 知识点1 解直角三角形 INCLUDEPICTURE"L1.tif" INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\L1.tif" \* MERGEFORMATINET INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\L1.tif" \* MERGEFORMATINET [2023广州越秀区二模在△ABC中，∠C＝90°，AB＝15，sin B＝，则BC等于(　　) A．25 B．12 C．9 D．16 变式1如图，在△ABC中，AB＝AC＝13，BD⊥AC于点D，sin A＝. INCLUDEPICTURE"image3382.tif" INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\image3382.tif" \* MERGEFORMATINET INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\image3382.tif" \* MERGEFORMATINET (1)求BD的长； (2)求tan C的值． 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 知识点2 解非直角三角形 INCLUDEPICTURE"L2.tif" INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\L2.tif" \* MERGEFORMATINET INCLUDEPICTURE "D:\\课件\\九数JJ河北（北京）\\L2.tif" \* MERGEFORMATINET 如图，在△ABC中，∠B＝30°，∠C＝45°，AC＝ ... ...