Make an uncovered cylindrical tin oil drum with a height of 8 decimeters and a bottom diameter of 4 decimeters. At least how many square decimeters are used for the iron sheet?
做一个没盖的圆柱形铁皮油桶，高8分米，底面直径是4分米．至少用铁皮多少平方分米？
<gadget id="calculator">3.14 * 4 * 8</gadget>
<output>100.48</output>

<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<gadget id="calculator">100.48 + 12.56</gadget>
<output>113.04</output>

<result>113.04</result>