If a cylinder with a base diameter of 4 decimeters is cut off to a small cylinder with a height of 2 decimeters, how much square decimeters will the surface area of the original cylinder be reduced?
把一个底面直径4分米的圆柱体，截去一个高2分米的小圆柱体，原来的圆柱体表面积减少多少平方分米．
<gadget id="calculator">3.14 * 4 * 2</gadget>
<output>25.12</output>

<result>25.12</result>