A cylindrical iron bucket without a lid, the bottom diameter is 6 decimeters, and the height is 1 meter. About how many square decimeters of iron sheet are used to make this barrel.
一个无盖的圆柱形铁皮桶，底面直径6分米，高1米．做这个桶大约用铁皮多少平方分米．
<gadget id="calculator">3.14 * 6</gadget>
<output>18.84</output>

<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">18.84 + 28.26</gadget>
<output>47.1</output>

<result>47.1</result>