如图,四边形ABCD内接于⊙O,若∠C=36°,则∠A的度数为()
A.36° | B.56° | C.72° | D.144° |
如图,∠AOB=100°,点C在⊙O上,且点C不与A、B重合,则∠ACB的度数为()
A.50° B.80°或50° C.130° D.50°或130°
如图,四边形ABCD是圆内接四边形,E是BC延长线上一点,若∠BAD=105°,则∠DCE的大小是()
A.115° | B.l05° | C.100° | D.95° |
如图,AB是⊙O的直径,C是⊙O上一点,AB=10,AC=6,OD⊥BC,垂足是D,则BD的长为()
A.2 | B.3 | C.4 | D.6 |
如图,在⊙O中,已知∠OAB=22.5°,则∠C的度数为()
A.135° | B.122.5° | C.115.5° | D.112.5° |