A conical heap of hummus has a base radius of 3 meters and a height of 2 meters. If these wheats are put into a cylindrical granary, it will only occupy 4/7 of the granary. It is known that the bottom area of the granary is 7 square meters, and the height of the granary is How much rice?
一个圆锥形胡麦堆，底面半径3米，高2米，如果把这些小麦装入一个圆柱形粮仓，只占粮仓的七分之四，已知粮仓的底面积是7平方米，粮仓的高多少米？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">(1/3) * 3.14 * 9 * 2</gadget>
<output>18.84</output>

<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">18.84 / (4/7) / 7</gadget>
<output>4.71</output>

<result>4.71</result>