A cylindrical tin bucket without a cover is 30 cm high and has a bottom radius of 10 cm. How many square decimeters of tin should be used to make a pair of such buckets?
一个无盖的圆柱形铁皮水桶，高是30厘米，底面半径10厘米，做一对这样水桶至少要用铁皮多少平方分米？
<gadget id="calculator">2 * 3.14 * 10 * 30</gadget>
<output>1_884</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<gadget id="calculator">1_884 + 314</gadget>
<output>2_198</output>

<gadget id="calculator">2_198 / 100</gadget>
<output>1_099/50 = around 21.98</output>

<result>1_099/50 = around 21.98</result>