A cylindrical oil barrel without a cover has a bottom circumference of 31.4 decimeters and a height of 60 decimeters. How many square decimeters of iron sheet are needed to make such an oil barrel?
一个无盖的圆柱形油桶，底面周长为31.4分米，高为60分米，做这样一个油桶要多少平方分米铁皮？
<gadget id="calculator">31.4 * 60</gadget>
<output>1_884</output>

<gadget id="calculator">31.4 / 3.14 / 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">1_884 + 78.5</gadget>
<output>1_962.5</output>

<result>1_962.5</result>