4.
如图,在△ABC中,∠C=90°,AC=BC,AD平分∠CAB,交BC于D,DE⊥AB于E,且AE=6cm,则△ABC的周长为( )
| A. | 24cm | B. | (12+6$\sqrt{2}$)cm | C. | 10cm | D. | (8+6$\sqrt{3}$)cm |
19.把方程2-$\frac{3x+2}{3}$=-$\frac{x-5}{6}$去分母后,正确的是( )
| A. | 12-(3x+2)=-(x-5) | B. | 12-2(3x+2)=-x-5 | C. | 2-2(3x+2)=-(x-5) | D. | 12-2(3x+2)=-(x-5) |
18.下列三条线段能组成三角形的是( )
| A. | 15,10,8 | B. | 15,23,8 | C. | 10,10,23 | D. | 18,10,8 |
17.近似数-0.03750的有效数字有( )个.
| A. | 3个 | B. | 4个 | C. | 5个 | D. | 6个 |
16.下列运算中,正确的是( )
0 290441 290449 290455 290459 290465 290467 290471 290477 290479 290485 290491 290495 290497 290501 290507 290509 290515 290519 290521 290525 290527 290531 290533 290535 290536 290537 290539 290540 290541 290543 290545 290549 290551 290555 290557 290561 290567 290569 290575 290579 290581 290585 290591 290597 290599 290605 290609 290611 290617 290621 290627 290635 366461
| A. | .$\sqrt{3}$+$\sqrt{2}$=$\sqrt{5}$ | B. | $\sqrt{(\sqrt{3}-2)^{2}}$=$\sqrt{3}$-2 | C. | $\sqrt{(-π)^{2}}$=π | D. | $\sqrt{(a+b)^{2}}$=a+b |