A cylindrical container with a base radius of 2 decimeters contains water. A conical plumb weight is completely immersed in the water, and the water level rises by 1 decimeter. What is the volume of the plumb weight?
一个底面半径是2分米的圆柱形容器内盛有水，把一个圆锥形铅锤完全浸入水中，水面上升1分米，这个铅锤的体积是多少π立方分米．
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">4 * 1</gadget>
<output>4</output>

<result>4</result>