To make a cylindrical tin bucket without a cover, the diameter of the bottom of the bucket is 4dm, and the height is 5dm, how many square decimeters of tin should be used at least?
做一个无盖的圆柱形铁皮水桶，水桶底面直径为4dm，高5dm，则至少要用铁皮多少平方分米？
<gadget id="calculator">3.14 * 4 * 5</gadget>
<output>62.8</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">62.8 + 12.56</gadget>
<output>75.36</output>

<result>75.36</result>