7.计算2sin45°的结果等于( )
| A. | $\frac{\sqrt{2}}{2}$ | B. | 1 | C. | $\sqrt{2}$ | D. | $\sqrt{3}$ |
3.计算tan60°的值等于( )
| A. | $\frac{\sqrt{3}}{3}$ | B. | $\frac{\sqrt{3}}{2}$ | C. | 1 | D. | $\sqrt{3}$ |
20.
如图,AB是⊙0的直径,弦CD⊥AB于E,连结OC、AD,且∠A=35°,则∠AOC=( )
| A. | 70° | B. | 105° | C. | 110° | D. | 140° |
19.一次数学测试,某小组五名同学的成绩如下表所示(有两个数据被遮盖)
那么被遮盖的两个数据依次是( )
| 同学 | A | B | C | D | E | 方差 | 平均成绩 |
| 得分 | 81 | 79 | 80 | 82 | 80 |
| A. | 78,2 | B. | 78,$\sqrt{2}$ | C. | 80,2 | D. | 80,$\sqrt{2}$ |
18.
如图,直线a,b被直线c所截,若a∥b,∠1=40°,∠2=70°,则∠3=( )
0 294590 294598 294604 294608 294614 294616 294620 294626 294628 294634 294640 294644 294646 294650 294656 294658 294664 294668 294670 294674 294676 294680 294682 294684 294685 294686 294688 294689 294690 294692 294694 294698 294700 294704 294706 294710 294716 294718 294724 294728 294730 294734 294740 294746 294748 294754 294758 294760 294766 294770 294776 294784 366461
| A. | 70° | B. | 100° | C. | 110° | D. | 120° |