A cylindrical water tank with a bottom diameter of 4 decimeters and a height of 5 decimeters, if a stone is immersed in the water, the water level will rise by 3 decimeters. What is the volume of this rock?
一个底面直径是4分米、高是5分米的圆柱形水箱，如果将一个石块浸入水中，水面上升3分米．这个石块的体积是多少？
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4 * 3</gadget>
<output>37.68</output>

<result>37.68</result>