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如图,A、B、C三点都在⊙O上,若∠BOC=80°,则∠A的度数等于( ) A....
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如图,A、B、C三点都在⊙O上,若∠BOC=80°,则∠A的度数等于( )
A.20°
B.40°
C.60°
D.80°
考点分析:
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如图,CD是⊙O的直径,A、B是⊙O上的两点,若∠ABD=20°,则∠ADC的度数为( )
A.40°
B.50°
C.60°
D.70°
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已知,如图弧BC与弧AD的度数之差为20°,弦AB与CD交于点E,∠CEB=60°,则∠CAB等于( )
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A.50°
B.45°
C.40°
D.35°
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如图,已知∠ACB是⊙O的圆周角,∠ACB=50°,则圆心角∠AOB是( )
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A.40°
B.50°
C.80°
D.100°
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下列图形中能够说明∠1>∠2的是( )
A.
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B.
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C.
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D.
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如图,A,B,C为⊙O上三点,∠ABC=60°,则∠AOC的度数为( )
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A.30°
B.60°
C.100°
D.120°
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