【单选题】
侧棱长为10,高为6的正三棱锥的底面积是( )
①
<img class="kfformula" src="20190809/1565327194325168.png" data-latex="60"/>
②
<img class="kfformula" src="20190809/1565327194151271.png" data-latex="48\sqrt {3}"/>
③
<img class="kfformula" src="20190809/1565327194214174.png" data-latex="24"/>
④
<img class="kfformula" src="20190809/1565327194795377.png" data-latex="30"/>
【单选题】
正四棱锥底面边长是2,高是1,则斜高是()
①
<img class="kfformula" src="20190809/1565327137897917.png" data-latex="\sqrt {2}"/>
②
<img class="kfformula" src="20190809/1565327137411071.png" data-latex="\sqrt {5}"/>
③
<img class="kfformula" src="20190809/1565327137707931.png" data-latex="2"/>
④
<img class="kfformula" src="20190809/1565327137840495.png" data-latex="\sqrt {3}"/>
【单选题】
正四棱锥的侧面是正三角形,则它的高与底面边长之比为 ()
①
<img class="kfformula" src="20190809/1565327345233053.png" data-latex="2:1"/>
②
<img class="kfformula" src="20190809/1565327345365743.png" data-latex="1:2"/>
③
<img class="kfformula" src="20190809/1565327345190290.png" data-latex="1:\sqrt {2}"/>
④
<img class="kfformula" src="20190809/1565327345759526.png" data-latex="\sqrt {2}:1"/>