A teacup with a base diameter of 6 cm is filled with water at a height of 7 cm. A small stone is placed in it, and the water rises to a height of 9 cm. What is the volume of the stone in cubic centimeters?
一个底面直径是6厘米的茶杯里，装有7厘米高的水，放入一块小石头，水面上升到9厘米，这个石头的体积是多少立方厘米？
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">9 - 7</gadget>
<output>2</output>

<gadget id="calculator">3.14 * 9 * 2</gadget>
<output>56.52</output>

<result>56.52</result>