一个圆锥的母线长为4,侧面积为12π,则这个圆锥的底面圆的半径是______.
∵母线为4,设圆锥的底面半径为x,
∴圆锥的侧面积=π×4×x=12π.
解得:x=3.
故答案为:3.
A disk with a horizontal line through its center,equivalent to the summer load line,is called the().
A.deadrise mark
B.maximum allowable draft mark
C.plimsoll mark
D.tonnage mark
煤矿综合防尘的措施?