A cylindrical wood with a length of 4dm and a base radius of 10cm is cut into two small cylinders, how much is the surface area increased?
一根长4dm的圆柱形木料，底面半径是10cm，将它截成两个小圆柱体后，表面积增加了多少．
<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

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

<result>628</result>