Build a cylindrical biogas digester with a bottom diameter of 4 meters and a depth of 2.5 meters. Put cement on the four walls and bottom of the pool, how many square meters is the cement plastered area?
修建一个圆柱形沼气池，底面直径4米，深2.5米．在池的四壁与下底抹上水泥，抹水泥面积是多少平方米？
<gadget id="calculator">3.14 * 4 * 2.5</gadget>
<output>31.4</output>

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

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

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<gadget id="calculator">31.4 + 12.56</gadget>
<output>43.96</output>

<result>43.96</result>