【单选题】
A点坐标为（10、20、30），B点坐标为（30、20、30）则AB距离为______。
①
Normal
0
7.8 磅
0
2
false
false
false
EN-US
ZH-CN
X-NONE
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mso-style-parent:"";
mso-padding-alt:0cm 5.4pt 0cm 5.4pt;
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正垂线
②
Normal
0
7.8 磅
0
2
false
false
false
EN-US
ZH-CN
X-NONE
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侧垂线
③
Normal
0
7.8 磅
0
2
false
false
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ZH-CN
X-NONE
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mso-para-margin-bottom:.0001pt;
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正平线
④
Normal
0
7.8 磅
0
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false
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X-NONE
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mso-hansi-theme-font:minor-latin;
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铅垂线
【单选题】
测量上使用的平面直角坐标系的坐标轴是（ ）。
①
南北方向的坐标轴为y轴，向北为正;东西方向的为x轴，向东为正
②
南北方向的坐标轴为y轴，向南为正;东西方向的为x轴，向西为正
③
南北方向的坐标轴为x轴，向北为正;东西方向的为y轴，向东为正
④
南北方向的坐标轴为x轴，向南为正;东西方向的为y轴，向西为正