A conical sandy land has a base radius of 3 meters and a height of 20dm. If this pile of sand is used to pave a 4mm thick road on a 5m wide road, how many meters can be paved?
一个圆锥形沙地，底面半径3米，高是20dm．用这堆沙子在5米宽的公路上铺4mm厚的路面，可以铺多少米？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

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

<gadget id="calculator">4 / 1_000</gadget>
<output>1/250 = around 0.004</output>

<gadget id="calculator">5 * (1/250)</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">2 / (1/50)</gadget>
<output>100</output>

<gadget id="calculator">(1/3) * 3.14 * 9 * 100</gadget>
<output>942</output>

<result>942</result>