If a cylinder with a radius of 3 meters and a height of 4 meters is cut into a cone with the same base and height, what is the volume cut off?
把一个半径为3米，高为4米的圆柱削成一个和它等底等高的圆锥，削掉的体积是多少．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">3.14 * 9 * (2/3)</gadget>
<output>18.84</output>

<result>18.84</result>