11.
两组邻边分别相等的四边形我们称它为筝形.如图,在四边形ABCD中,AB=AD,BC=DC,AC与BD相交于点O,下列判断正确的有( )
①AC⊥BD;
②AC、BD互相平分;
③AC平分∠BCD;
④∠ABC=∠ADC=90°;
⑤筝形ABCD的面积为$\frac{1}{2}$AC•BD.
①AC⊥BD;
②AC、BD互相平分;
③AC平分∠BCD;
④∠ABC=∠ADC=90°;
⑤筝形ABCD的面积为$\frac{1}{2}$AC•BD.
| A. | ①③⑤ | B. | ①③④ | C. | ③④⑤ | D. | ①④⑤ |
9.
将一副三角板如图所示放置,且满足BC∥DE,则∠AFC=( )
| A. | 80° | B. | 75° | C. | 70° | D. | 65° |
5.
如图,在矩形ABCD中,AD=$\sqrt{2}$AB,∠BAD的平分线交BC于点E,DH⊥AE于点H,连接DE,下列结论:①∠AED=∠CED;②△AED为等腰三角形;③EH=CE;④图中有3个等腰三角形.结论正确的个数为( )
0 296448 296456 296462 296466 296472 296474 296478 296484 296486 296492 296498 296502 296504 296508 296514 296516 296522 296526 296528 296532 296534 296538 296540 296542 296543 296544 296546 296547 296548 296550 296552 296556 296558 296562 296564 296568 296574 296576 296582 296586 296588 296592 296598 296604 296606 296612 296616 296618 296624 296628 296634 296642 366461
| A. | 1个 | B. | 2个 | C. | 3个 | D. | 4个 |