To make a cylindrical bucket without a cover, the height is 6 cm, and the radius of the bottom surface is 4 cm. What is the minimum square centimeter of iron sheet needed to make this bucket?
做一个无盖的圆柱形水桶，高是6厘米，底面半径是4厘米，做这个水桶至少需要铁皮多少平方厘米．
<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

<gadget id="calculator">3.14 * 4 * 2 * 6</gadget>
<output>150.72</output>

<gadget id="calculator">50.24 + 150.72</gadget>
<output>200.96</output>

<result>200.96</result>