The circumference of the bottom of a cylindrical glass bottle is 6.28 cm, half a bottle of water is filled in it, a stone is put in it, and the water level rises by 20 mm, what is the volume of the stone?
一个圆柱形玻璃瓶底面周长是6.28厘米，里面装了半瓶水，把一块石头放进去，水面升高20毫米，这块石头体积是多少．
<gadget id="calculator">6.28 / 3.14 / 2</gadget>
<output>1</output>

<gadget id="calculator">20 / 10</gadget>
<output>2</output>

<gadget id="calculator">1 ** 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 1 * 2</gadget>
<output>6.28</output>

<result>6.28</result>