The radius of the bottom of the gasoline tank is 2dm and the height is 8dm. How much iron sheet does it take to make a petrol can like this?
汽油桶底面半径是2dm，高是8dm．做一个这样的汽油桶需要多少铁皮？
<gadget id="calculator">2 * 3.14 * 2 * 8</gadget>
<output>100.48</output>

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

<gadget id="calculator">3.14 * 4 * 2</gadget>
<output>25.12</output>

<gadget id="calculator">100.48 + 25.12</gadget>
<output>125.6</output>

<result>125.6</result>