The radius of the base of a cone is twice the radius of the base of a cylinder, and the height is (1/2) that of the cylinder, then the volume of the cone is the volume of the cylinder.
一个圆锥的底面半径是一个圆柱底面半径的2倍，而高则是圆柱的(1/2)，则圆锥的体积是圆柱的多少．
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

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

<gadget id="calculator">(1/3) / 6.28</gadget>
<output>0.053079</output>

<gadget id="calculator">3.14 * 4 * 1 * 0.053079</gadget>
<output>0.666672</output>

<result>0.666672</result>