20.
如图,正方形ABCD由四个相同的大长方形,四个相同的小长方形以及一个小正方形组成.其中四个大长方形的长和宽分别是小长方形长和宽的3倍,若中间小正方形的面积为1,则大正方形ABCD的面积是( )
| A. | 49 | B. | 64 | C. | 81 | D. | 100 |
17.已知一个表面积为12㎡的正方体,则这个正方体的棱长为( )
0 286569 286577 286583 286587 286593 286595 286599 286605 286607 286613 286619 286623 286625 286629 286635 286637 286643 286647 286649 286653 286655 286659 286661 286663 286664 286665 286667 286668 286669 286671 286673 286677 286679 286683 286685 286689 286695 286697 286703 286707 286709 286713 286719 286725 286727 286733 286737 286739 286745 286749 286755 286763 366461
| A. | 1m | B. | $\sqrt{2}$m | C. | 6m | D. | 3m |