1.如图①,△ABC中,AB=AC,CD⊥AB于D,则∠DCB等于( )A.½∠ACB B.½∠ACD C.½∠A D.∠A2.如图②,△ABC中,AB=BD=AC,AD=CD,则∠ADB的度数是( )A.36° B.45° C.60° D.72°3.如图③,△ABC中,∠ACB=90°,BA的垂直
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![1.如图①,△ABC中,AB=AC,CD⊥AB于D,则∠DCB等于( )A.½∠ACB B.½∠ACD C.½∠A D.∠A2.如图②,△ABC中,AB=BD=AC,AD=CD,则∠ADB的度数是( )A.36° B.45° C.60° D.72°3.如图③,△ABC中,∠ACB=90°,BA的垂直](/uploads/image/z/11158980-60-0.jpg?t=1.%E5%A6%82%E5%9B%BE%E2%91%A0%2C%E2%96%B3ABC%E4%B8%AD%2CAB%3DAC%2CCD%E2%8A%A5AB%E4%BA%8ED%2C%E5%88%99%E2%88%A0DCB%E7%AD%89%E4%BA%8E%EF%BC%88+%EF%BC%89A.%26%23189%3B%E2%88%A0ACB+B.%26%23189%3B%E2%88%A0ACD+C.%26%23189%3B%E2%88%A0A+D.%E2%88%A0A2.%E5%A6%82%E5%9B%BE%E2%91%A1%2C%E2%96%B3ABC%E4%B8%AD%2CAB%3DBD%3DAC%2CAD%3DCD%2C%E5%88%99%E2%88%A0ADB%E7%9A%84%E5%BA%A6%E6%95%B0%E6%98%AF%EF%BC%88+%EF%BC%89A.36%C2%B0+B.45%C2%B0+C.60%C2%B0+D.72%C2%B03.%E5%A6%82%E5%9B%BE%E2%91%A2%2C%E2%96%B3ABC%E4%B8%AD%2C%E2%88%A0ACB%3D90%C2%B0%2CBA%E7%9A%84%E5%9E%82%E7%9B%B4)
1.如图①,△ABC中,AB=AC,CD⊥AB于D,则∠DCB等于( )A.½∠ACB B.½∠ACD C.½∠A D.∠A2.如图②,△ABC中,AB=BD=AC,AD=CD,则∠ADB的度数是( )A.36° B.45° C.60° D.72°3.如图③,△ABC中,∠ACB=90°,BA的垂直
1.如图①,△ABC中,AB=AC,CD⊥AB于D,则∠DCB等于( )
A.½∠ACB B.½∠ACD C.½∠A D.∠A
2.如图②,△ABC中,AB=BD=AC,AD=CD,则∠ADB的度数是( )
A.36° B.45° C.60° D.72°
3.如图③,△ABC中,∠ACB=90°,BA的垂直平分线交CB于点D,若AB=10,AC=5,则图中等于60°的角的个数为( )
A.2 B.3 C.4 D.5
4.如图④,EA⊥AB,BC⊥AB,EA=AB=2BC,D为AB中点,有以下结论:
(1)DE=AC(2)DE⊥AC(3)∠CAB=30°(4)∠EAF=∠ADE.其中结论正确的是( )
A.(1)(3) B.(2)(3) C.(3)(4) D.(1)(2)(4)
1.如图①,△ABC中,AB=AC,CD⊥AB于D,则∠DCB等于( )A.½∠ACB B.½∠ACD C.½∠A D.∠A2.如图②,△ABC中,AB=BD=AC,AD=CD,则∠ADB的度数是( )A.36° B.45° C.60° D.72°3.如图③,△ABC中,∠ACB=90°,BA的垂直
1、C 作AM⊥BC于M点,△AMB∽△DCB,等腰三角形三线合一.
2、D ∠ADB是△ADC的外角,AD=CD,所以∠ADB=2∠ACD,AB=AC,∠ACD=∠ABC,所以∠ADB=180°/(5/2)=72°.
3、C ∠ADC,∠ADE,∠A,∠BDE
4、D AB=2BC,∠CAB≠30°.