14.正六边形具备而菱形不具备的性质是( )
| A. | 对角线互相平分 | B. | 对角线互相垂直 | ||
| C. | 对角线相等 | D. | 每条对角线平分一组对边 |
12.
如图,在矩形ABCD中,下列结论不正确的是( )
| A. | △AOB的等腰三角形 | |
| B. | S△ABO=S△ADO | |
| C. | AC⊥BD | |
| D. | 当∠ABD=45°时,矩形ABCD会变成正方形 |
11.正方形的一条对角线长是8,那么它的面积是( )
0 285441 285449 285455 285459 285465 285467 285471 285477 285479 285485 285491 285495 285497 285501 285507 285509 285515 285519 285521 285525 285527 285531 285533 285535 285536 285537 285539 285540 285541 285543 285545 285549 285551 285555 285557 285561 285567 285569 285575 285579 285581 285585 285591 285597 285599 285605 285609 285611 285617 285621 285627 285635 366461
| A. | 32 | B. | 8 | C. | 64 | D. | 16 |