15.下列命题中,真命题是( )
0 294370 294378 294384 294388 294394 294396 294400 294406 294408 294414 294420 294424 294426 294430 294436 294438 294444 294448 294450 294454 294456 294460 294462 294464 294465 294466 294468 294469 294470 294472 294474 294478 294480 294484 294486 294490 294496 294498 294504 294508 294510 294514 294520 294526 294528 294534 294538 294540 294546 294550 294556 294564 366461
| A. | 两条对角线相等的四边形是矩形 | |
| B. | 两条对角线互相垂直且平分的四边形是正方形 | |
| C. | 等边三角形既是轴对称图形又是中心对称图形 | |
| D. | 有一个角是60°的等腰三角形是等边三角形 |