A cylindrical bucket without a lid has a base radius of 20 cm and a height of 50 cm. How many square decimeters of iron sheet is needed to make this bucket? (reserve the whole square decimeter)
一个圆柱形的无盖水桶，底面半径是20厘米，高是50厘米．做这个水桶至少需要铁皮多少平方分米？(保留整平方分米数)
<gadget id="calculator">3.14 * 2 * 20 * 50</gadget>
<output>6_280</output>

<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

<gadget id="calculator">3.14 * 400</gadget>
<output>1_256</output>

<gadget id="calculator">6_280 + 1_256</gadget>
<output>7_536</output>

<gadget id="calculator">7_536 / 100</gadget>
<output>1_884/25 = around 75.36</output>

<result>1_884/25 = around 75.36</result>