2.
如图,△ABC和△DBE中,AB=CB,DB=EB,∠ABC=∠DBE=50°.若∠BDC=25°,AD=4,DE=$\sqrt{13}$,则CD的长为( )
| A. | $\sqrt{2}$ | B. | $\sqrt{3}$ | C. | $\frac{\sqrt{13}}{2}$ | D. | 2 |
19.顺次连接一个矩形各边的中点,得到的四边形一定是( )
| A. | 菱形 | B. | 矩形 | C. | 正方形 | D. | 梯形 |
18.下列二次根式中,最简二次根式是( )
| A. | $\sqrt{\frac{1}{3}}$ | B. | $\sqrt{0.3}$ | C. | $\sqrt{3}$ | D. | $\sqrt{20}$ |
17.数据5,3,2,1,4的中位数是( )
| A. | 4 | B. | 1 | C. | 2 | D. | 3 |
16.
如图,数轴上点P表示的数可能是( )
0 284717 284725 284731 284735 284741 284743 284747 284753 284755 284761 284767 284771 284773 284777 284783 284785 284791 284795 284797 284801 284803 284807 284809 284811 284812 284813 284815 284816 284817 284819 284821 284825 284827 284831 284833 284837 284843 284845 284851 284855 284857 284861 284867 284873 284875 284881 284885 284887 284893 284897 284903 284911 366461
| A. | $\sqrt{2}$ | B. | $\sqrt{5}$ | C. | $\sqrt{10}$ | D. | $\sqrt{15}$ |