A conical pile of coal has a circumference of 31.4 meters and a height of 3 meters. If each cubic meter of coal weighs 2 tons, how many tons does this pile of coal weigh?
一个圆锥形的煤堆，测得它的底面周长是31.4米，高3米，如果每立方米煤重2吨，这堆煤大约重多少吨？
<gadget id="calculator">31.4 / 3.14 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

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

<gadget id="calculator">3.14 * 25 * 3 * (1/3) * 2</gadget>
<output>157</output>

<result>157</result>