To make a cylindrical tin bucket without a cover, the radius of the bottom is 10 cm, and the height is 50 cm. How many square centimeters of tin is needed?
做一个无盖的圆柱形铁皮水桶，底面半径是10厘米，高50厘米，需要铁皮多少平方厘米？
<gadget id="calculator">2 * 3.14 * 10 * 50</gadget>
<output>3_140</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<gadget id="calculator">3_140 + 314</gadget>
<output>3_454</output>

<result>3_454</result>