A cylinder-shaped reservoir has a circumference of 31.4 meters measured from the inside and a depth of 2.4 meters. Cement is applied to its inner wall and bottom. What is the area of the plastered part in square meters?
一个圆柱体形的蓄水池，从里面量底面周长31.4米，深2.4米，在它的内壁与底面抹上水泥．抹水泥部分的面积是多少平方米？
<gadget id="calculator">31.4 / 3.14 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<gadget id="calculator">3.14 * 5 * 2 * 2.4</gadget>
<output>75.36</output>

<gadget id="calculator">78.5 + 75.36</gadget>
<output>153.86</output>

<result>153.86</result>