浙教版八年级上数学第二章《特殊三角形》试卷.doc

新八年级暑期调研第二章《特殊三角形》()
(数学部分)
一、选择题(每小题3分,共27分)
°,那么一个底角的度数为···················( )
° ° ° °
,对称轴最多的是············································( )

:①等边三角形是轴对称图形;②等边三角形是中心对称图形,结果是···( )
A.①②都正确 B.①②都错误 C.①正确,②错误 D.①错误,②正确
4.△ABC中,∠A:∠B:∠C=4:5:9,则△ABC是····························( )
,且∠A=90° ,且∠B=90°
,且∠C=90°
,不能组成直角三角形的是······························( )
,4,5 ,12,13 ,8,10 ,5,6
,在Rt△ABC中,CD是斜边AB上的中线,则图中与CD相等的线段有·····( ) 、BD与BC
B
D
C
A
(第6题) (第7题)
,△ABC中,∠C=90°,AB的中垂线DE交AB于E,交BC于D,若AB=10,AC=6,
则△ACD的周长为······················································( )

,△ABC中,AB=AC=6,BC=8,AD平分∠BAC交BC于点D,DE//AC交AB于点E,则△BDE的周长为··············································( )
A. B.
(第8题) (第9题)
,△ABC中,∠ACB=90°,D在BC上,E为AB之中点,AD、CE相交于F,且AD=∠B=20°,则∠DFE等于············································( )
° ° ° °
二、填空题(每小题4分,共20分)
°.
°,则较大的锐角的度数为°
△ABC中,∠C=90°∠B=60°,若BC=2cm,则AB= cm.
,等腰△ABC中,AB=AC,AD是底边上的高,若AB=5,BC=6,则AD= .
(第13题) (第14题)
,△ABC是边长为2的等边三角形,点D是BC边上的任意点,DE⊥AB于E点,DF⊥AC于F点,则DE+DF= .
三、解答题
:等腰△ABC的底边BC=8,且AC-BC=:等腰三角形的周长.(5分)
:等边△ABC中,BD=CE,AD与BE相交于P点,
求:∠APE的度数. (5分)