A cylindrical iron bottle has a bottom diameter of 10 cm and a height of 30 cm. What is the minimum square centimeter of iron sheet needed to make this iron bottle?
一个圆柱形铁瓶底面直径是10厘米，高30厘米．做这个铁瓶最少需要铁皮多少平方厘米？
<gadget id="calculator">3.14 * 10 * 30</gadget>
<output>942</output>

<gadget id="calculator">10 / 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">942 + 78.5</gadget>
<output>1_020.5</output>

<result>1_020.5</result>