A cylindrical iron sheet bucket without a cover, with a height of 5dm and a bottom diameter of 0.4m, how much iron sheet should be used to make a pair of such buckets?
一种没有盖的圆柱形铁皮水桶，高5dm，底面直径0.4m，做一对这样的水桶至少要用多少铁皮？
<gadget id="calculator">3.14 * 0.4 * 10 * 5</gadget>
<output>62.8</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">0.4 * 5</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>