A cylinder and a cone have the same volume and height, the area of the base of the cylinder is 30 square decimeters, what is the area of the base of the cone in square decimeters?
一个圆柱与圆锥的体积相等，高也相等，圆柱的底面积是30平方分米，圆锥的底面积是多少平方分米．
<gadget id="calculator">30 * 3</gadget>
<output>90</output>

<result>90</result>