9.等腰△ABC中,过A作BC的垂线,垂足为D,且AD=$\frac{1}{2}$BC,则△ABC底角的度数为( )
| A. | 45° | B. | 45°或75° | C. | 45°或15°或75° | D. | 45°或60° |
6.
如图,⊙O的直径AB=2,点C在⊙O上,弦AC=1,则∠D的度数是( )
| A. | 30° | B. | 60° | C. | 45° | D. | 75° |
5.
已知直线AB,射线OC,OD都在如图所示的量角器上,点O在直线AB上,则下列判断中不正确的是( )
0 291898 291906 291912 291916 291922 291924 291928 291934 291936 291942 291948 291952 291954 291958 291964 291966 291972 291976 291978 291982 291984 291988 291990 291992 291993 291994 291996 291997 291998 292000 292002 292006 292008 292012 292014 292018 292024 292026 292032 292036 292038 292042 292048 292054 292056 292062 292066 292068 292074 292078 292084 292092 366461
| A. | ∠AOC=56° | B. | ∠AOD=134° | C. | ∠AOC<∠COD | D. | ∠BOD与∠BOC互补 |