conical sand pile has a bottom area of 12.56 square meters and a height of 0.9 meters. How long can you pave a road with a cross-section of 0.2 square meters on the road with this pile of sand?
一个圆锥形沙堆，底面积是12.56平方米，高0.9米．用这堆沙在公路上铺横截面为0.2平方米的路面，能铺多长？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">0.9 / 0.2</gadget>
<output>4.5</output>

<gadget id="calculator">(1/3) * 12.56 * 4.5</gadget>
<output>18.84</output>

<result>18.84</result>