The radius of the base of a cylinder of iron is 10 cm. If it is cut in the middle and divided into two equal cylinders, how many square centimeters will the surface area increase?
一个圆柱铁块的底面半径是10厘米，如果把它从中间截开，分成两个相等的圆柱，表面积增加多少平方厘米．
<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100 * 2</gadget>
<output>628</output>

<result>628</result>