Divide a cylinder with a radius and a height of 1 decimeter into several equal parts along the radius of the bottom surface, cut it and assemble it into an approximate cuboid, how many square decimeters does the surface area of the rectangle increase?
把一个半径和高都是1分米的圆柱体沿底面半径平均分成若干等份，切开拼成一个近似的长方体，这个长方形的表面积增加了多少平方分米．
<gadget id="calculator">1 * 1 * 2</gadget>
<output>2</output>

<result>2</result>