16.
若AB是⊙O的直径,CD是⊙O的弦,∠ABD=55°,则∠BCD的度数为( )
| A. | 25° | B. | 35° | C. | 45° | D. | 65° |
15.点P(3,5)关于原点中心对称的点的坐标是( )
| A. | (5,3) | B. | (-3,5) | C. | (3,-5) | D. | (-3,-5) |
13.
AB为⊙O的直径,弦CD⊥AB于点E,已知CD=16,OE=6,则⊙O的直径为( )
| A. | 8 | B. | 10 | C. | 16 | D. | 20 |
12.一元二次方程(x-1)(x+2)=0的解是( )
| A. | 1 | B. | 1或-2 | C. | -1或2 | D. | -2 |
11.下列线段成比例的有( )
0 293902 293910 293916 293920 293926 293928 293932 293938 293940 293946 293952 293956 293958 293962 293968 293970 293976 293980 293982 293986 293988 293992 293994 293996 293997 293998 294000 294001 294002 294004 294006 294010 294012 294016 294018 294022 294028 294030 294036 294040 294042 294046 294052 294058 294060 294066 294070 294072 294078 294082 294088 294096 366461
| A. | 1,2,3,4 | B. | $\sqrt{2}$,$\sqrt{3}$,1,$\sqrt{6}$ | C. | 2,4,6,8 | D. | 2,5,3,10 |