14.
如图,△ABC中,BD平分∠ABC,EF垂直平分BC交BC于点E,交BD于点F,连接CF,若∠A=60°,∠ABD=25°,则∠ACF的度数为( )
| A. | 25° | B. | 45° | C. | 50° | D. | 70° |
13.如果下列各组数是三角形的三边,那么不能组成直角三角形的一组数是( )
| A. | 7,24,25 | B. | $\frac{7}{2}$,$\frac{9}{2}$,$\frac{11}{2}$ | C. | 3,4,5 | D. | 4,$\frac{15}{2}$,$\frac{17}{2}$ |
9.若三角形的三边长分别为$\sqrt{2}$,$\sqrt{6}$,2,则此三角形的面积为( )
| A. | $\frac{\sqrt{2}}{2}$ | B. | $\frac{\sqrt{3}}{2}$ | C. | $\sqrt{2}$ | D. | $\sqrt{3}$ |
8.
如图,菱形ABCD的周长为8cm,高AE的长为$\sqrt{3}$cm,则对角线BD的长为( )
| A. | 2cm | B. | 3cm | C. | $\sqrt{3}$cm | D. | 2$\sqrt{3}$cm |
5.
如图,平行四边形ABCD中,∠ABC=45°,E、F分别在CD和BC的延长线上,AE∥BD,EF⊥BC,AB=1,则EF的长是( )
0 285449 285457 285463 285467 285473 285475 285479 285485 285487 285493 285499 285503 285505 285509 285515 285517 285523 285527 285529 285533 285535 285539 285541 285543 285544 285545 285547 285548 285549 285551 285553 285557 285559 285563 285565 285569 285575 285577 285583 285587 285589 285593 285599 285605 285607 285613 285617 285619 285625 285629 285635 285643 366461
| A. | 1.5 | B. | $\sqrt{2}$ | C. | $\sqrt{3}$ | D. | 2 |