On the construction site, a cement pile was driven 3 meters into the ground, and 4 meters were exposed. What percentage of the total length is the part driven into the ground?
建筑工地上有一根水泥桩打入地下3米，露出4米．打入地下部分占全长的几分之几？
<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<result>3/7 = around 0.428571</result>