【单选题】
已知A、B、C三点坐标分别为（10、20、30）（20、40、60）、（30、60、90），则A、B、C三点______。
①
Normal
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7.8 磅
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2
false
false
false
EN-US
ZH-CN
X-NONE
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表示一个平面
②
Normal
0
7.8 磅
0
2
false
false
false
EN-US
ZH-CN
X-NONE
/* Style Definitions */
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mso-style-parent:"";
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mso-para-margin:0cm;
mso-para-margin-bottom:.0001pt;
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mso-bidi-font-size:11.0pt;
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mso-hansi-font-family:等线;
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mso-font-kerning:1.0pt;}
不能表示一个平面
③
Normal
0
7.8 磅
0
2
false
false
false
EN-US
ZH-CN
X-NONE
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table.MsoNormalTable
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mso-tstyle-colband-size:0;
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mso-style-parent:"";
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mso-para-margin:0cm;
mso-para-margin-bottom:.0001pt;
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mso-fareast-theme-font:minor-fareast;
mso-hansi-font-family:等线;
mso-hansi-theme-font:minor-latin;
mso-font-kerning:1.0pt;}
表示一个特殊位置平面
④
Normal
0
7.8 磅
0
2
false
false
false
EN-US
ZH-CN
X-NONE
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mso-tstyle-rowband-size:0;
mso-tstyle-colband-size:0;
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mso-style-parent:"";
mso-padding-alt:0cm 5.4pt 0cm 5.4pt;
mso-para-margin:0cm;
mso-para-margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:10.5pt;
mso-bidi-font-size:11.0pt;
font-family:等线;
mso-ascii-font-family:等线;
mso-ascii-theme-font:minor-latin;
mso-fareast-font-family:等线;
mso-fareast-theme-font:minor-fareast;
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mso-hansi-theme-font:minor-latin;
mso-font-kerning:1.0pt;}
无法判断
【多选题】
下列情况应该采取调和平均数的是?
①
已知各企业的计划任务数和计划完成程度，计算平均计划完成程度
②
已知各企业的实际完成数和计划完成程度，计算平均计划完成程度
③
已知各商品的销售单价和销售额，计算商品的平均销售单价
④
已知各商品的销售单价和销售数量，计算商品的平均销售单价
⑤
已知分组的粮食单位产量和各组粮食总量，计算总的平均粮食单位产量