Cut a cylindrical wood block with a base diameter of 4 cm and a height of 3 cm, and divide it into two small cylindrical blocks of the same shape and size. This is how much the surface area increases.
把一个底面直径为4厘米，高是3厘米的圆柱形木块切一刀，分成形状大小相同的两个小圆柱形木块，这是表面积增加多少．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

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

<gadget id="calculator">3.14 * 4 * 2</gadget>
<output>25.12</output>

<result>25.12</result>