cylindrical wooden barrel with a bottom diameter of 20cm is filled with water. An iron cone with a bottom diameter of 18cm and a height of 20cm is placed in the water. When the cone is taken out of the barrel, how many centimeters will the water in the barrel drop?
一个底面直径是20cm的圆柱形木桶中装着水，水中放着一个底面直径为18cm，高20cm的铁质圆锥体，当圆锥体从桶中取出后，桶内的水将下降多少厘米？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">9 ** 2</gadget>
<output>81</output>

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

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<gadget id="calculator">20 / 314</gadget>
<output>10/157 = around 0.063694</output>

<gadget id="calculator">(1/3) * 3.14 * 81 * (10/157)</gadget>
<output>5.4</output>

<result>5.4</result>