用尺规作图法。
一、√3的作法,如图:
1、过点A作数轴的垂线L1;
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/77c6a7efce1b9d16b72b997bfddeb48f8c54643f?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
2、在直线L1上截取AM=1,连接OM,根据勾股定理,OM=√OA2+AM2=√2;
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/3812b31bb051f81941f70050d4b44aed2f73e7de?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
3、过点M作OM的垂线L2;
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/48540923dd54564ecc7ae623bdde9c82d1584f88?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
4、在L2上截取MN=1,连接ON,根据勾股定理,ON=√OM2+MN2=√3;
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/aec379310a55b3195dff806f4da98226cffc17a1?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
5、以原点O为圆心,ON长为半径画弧,与数轴交于点P,点P坐标就是√3。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/6159252dd42a28343ae7341155b5c9ea15cebf62?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
二、√5的作法,如图:
1、过点B作数轴的垂线L3;
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/18d8bc3eb13533fae8e29134a6d3fd1f41345b57?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
2、在L3上截取BQ=1,连接OQ,根据勾股定理,OQ=√OB2+BQ2=√5;
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/a8ec8a13632762d010afa6a5aeec08fa513dc613?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
3、以原点O为圆心,OQ长为半径画弧,与数轴交于点S,点S坐标就是√5。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/fc1f4134970a304e54e1a2e0dfc8a786c8175cec?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)