A cone of sand has a diameter of 6m at the bottom and a height of 4m. If each cubic meter of sand weighs 0.5 tons, how many tons does the pile of sand weigh?
一个圆锥沙堆，底面直径6m，高4m，如果每立方米的沙重0.5吨，这堆沙子重多少吨？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

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

<gadget id="calculator">(1/3) * 3.14 * 9 * 4 * 0.5</gadget>
<output>18.84</output>

<result>18.84</result>