A conical grain mound has a bottom circumference of 25.12 meters and a height of 3 meters. If each cubic meter of grain weighs 0.7 tons, how much does this heap of grain weigh?
一个圆锥形谷堆，底面周长25.12米，高3米，若每立方米谷重0.7吨，这堆谷重多少？
<gadget id="calculator">25.12 / 3.14 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

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

<gadget id="calculator">3.14 * 16 * 3 * (1/3) * 0.7</gadget>
<output>35.168</output>

<result>35.168</result>