How many square decimeters of iron sheet is required to make a cylindrical bucket with a diameter of 4 decimeters and a height of 5 decimeters without a cover?
用铁皮做一个直径为4分米、高5分米的无盖的圆柱形水桶，至少需要多少平方分米的铁皮？
<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>