A cylindrical bucket with a cover is 5 decimeters in height and 12.56 decimeters in circumference at the bottom. How many square decimeters of iron sheets are needed to make such a bucket?
一个有盖的圆柱形水桶，高5分米，底面周长12.56分米，做这样一个水桶至少要用铁皮多少平方分米．
<gadget id="calculator">12.56 * 5</gadget>
<output>62.8</output>

<gadget id="calculator">2 * 3.14</gadget>
<output>6.28</output>

<gadget id="calculator">12.56 / 6.28</gadget>
<output>2</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4 * 2</gadget>
<output>25.12</output>

<gadget id="calculator">62.8 + 25.12</gadget>
<output>87.92</output>

<result>87.92</result>