A:30,8
B:80,6
C:60,4
D:20,4……8
已知圆锥的侧面积为15πcm2,底面半径为3cm,则圆锥的高是____
毫无疑问,懂得一些急救知识很有必要,因为危险无处不在。
____ ____ ____ ____ that it is necessary to know some knowledge of first aid as dangers lie everywhere.