4.把20克糖溶解在80克水中,糖水的含糖率是( )
| A. | 20% | B. | 80% | C. | 100% | D. | 无法计算 |
19.
如图,AD∥BC,AD⊥AB,点A,B在y轴上,CD与x轴交于点E(2,0),且AD=DE,BC=2CE,则BD与x轴交点F的横坐标为( )
| A. | $\frac{2}{3}$ | B. | $\frac{3}{4}$ | C. | $\frac{4}{5}$ | D. | $\frac{5}{6}$ |
16.以下列长度的三条线段组成的三角形中,面积最大的是( )
0 298498 298506 298512 298516 298522 298524 298528 298534 298536 298542 298548 298552 298554 298558 298564 298566 298572 298576 298578 298582 298584 298588 298590 298592 298593 298594 298596 298597 298598 298600 298602 298606 298608 298612 298614 298618 298624 298626 298632 298636 298638 298642 298648 298654 298656 298662 298666 298668 298674 298678 298684 298692 366461
| A. | 2,3,4 | B. | 3,3,4 | C. | 3,4,5 | D. | 3,4,6 |