1.同一时刻,身高1.72m的小明在阳光下影长为0.86米;小宝在阳光下的影长为0.64m,则小宝的身高为( )
| A. | 1.28m | B. | 1.13m | C. | 0.64m | D. | 0.32m |
20.
如图,在平面直角坐标系中,点P(-1,2)向右平移3个单位长度后的坐标是( )
| A. | (2,2) | B. | (-4,2) | C. | (-1,5) | D. | (-1,-1) |
19.下列运算正确的是( )
| A. | x2x3=x6 | B. | (xy)3=x3y | C. | 3x+2x=5x | D. | (x-1)2=x2-1 |
18.下列数是无理数的是( )
0 288307 288315 288321 288325 288331 288333 288337 288343 288345 288351 288357 288361 288363 288367 288373 288375 288381 288385 288387 288391 288393 288397 288399 288401 288402 288403 288405 288406 288407 288409 288411 288415 288417 288421 288423 288427 288433 288435 288441 288445 288447 288451 288457 288463 288465 288471 288475 288477 288483 288487 288493 288501 366461
| A. | π | B. | $\frac{1}{3}$ | C. | $\sqrt{9}$ | D. | 0 |