Build a cylindrical biogas tank with a bottom diameter of 6 meters and a depth of 4 meters. Put cement on the inner wall and lower bottom of the tank. What is the area of the cemented part?
修建一个圆柱形沼气池，底面直径是6米，深4米，在池的内壁与下底面抹上水泥，抹水泥部分的面积是多少平方？
<gadget id="calculator">3.14 * 6 * 4</gadget>
<output>75.36</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

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

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<gadget id="calculator">75.36 + 28.26</gadget>
<output>103.62</output>

<result>103.62</result>