cylindrical iron sheet bucket without a cover has a diameter and height of 6 decimeters. How many square decimeters of iron sheet are needed to make such a bucket?
一个无盖圆柱形铁皮水桶，直径和高都是6分米，做这样一个水桶至少需要铁皮多少平方分米？
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<gadget id="calculator">3.14 * 6 * 6</gadget>
<output>113.04</output>

<gadget id="calculator">28.26 + 113.04</gadget>
<output>141.3</output>

<result>141.3</result>