A cylindrical cistern has a bottom diameter of 4 meters and a depth of 30 decimeters. Put cement on the side and bottom of the pool, how many square meters is the area where the cement is applied?
一个圆柱形的蓄水池，底面直径是4米，深30分米．在池内的侧面和底面抹上水泥，抹水泥的面积是多少平方米？
<gadget id="calculator">30 / 10</gadget>
<output>3</output>

<gadget id="calculator">3.14 * 4 * 3</gadget>
<output>37.68</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">37.68 + 12.56</gadget>
<output>50.24</output>

<result>50.24</result>