生活中的椅子一般依据人体工学原理设计,如图为生活中一把椅子的侧面图,从人体脊柱的形势而言,当靠背角度
时,能产生较为接近自然腰部的形状,此时最舒适.已知
与地面平行,支撑杆
与地面夹角
,则制作时用螺丝固定时支撑杆
和
需构成夹角
为( )
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/17/278e1ee9-b58e-46f2-8d32-b52a0b5576ba.png?resizew=386)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/945430ff06a60054e9055ff05a592fb0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5220a2d77807be741297e7be70917082.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fabb884dc5f9609de491245463bbe9a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/17/278e1ee9-b58e-46f2-8d32-b52a0b5576ba.png?resizew=386)
A.![]() | B.![]() | C.![]() | D.![]() |
更新时间:2024-02-15 18:22:03
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【推荐1】如图,△ABC是等边三角形,DE//BC,若AB=7,BD=3,则△ADE的周长为( )
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【推荐2】如图,一副直角三角板图示放置,点
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【推荐1】如图,在正方形
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【推荐2】如图,锐角△ABC中,D,E分别是AB,AC边上的点,△ADC≌△ADC′,△AEB≌△AEB′,且C′D∥EB′∥BC,BE,CD交于点F.若∠BAC=35°,则∠BFC的大小是( )
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A.106° | B.108° | C.110° | D.112° |
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