Two cylinders and cones of equal volume have the same height. If the radius of the base of the cylinder is 2 cm, what is the area of the base of the cone?
两个体积相等的圆柱和圆锥，高也相等．圆柱的底面半径是2厘米，那么圆锥的底面积是多少π平方厘米．
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">4 * 3</gadget>
<output>12</output>

<result>12</result>