cylindrical piece of wood with a base radius of 2 cm is cut into three sections on average. At this time, the sum of the surface areas of the three pieces of wood is increased by how many square centimeters compared with the surface area of the original wood.
一根圆柱形木料，底面半径是2厘米，把它平均横截成三段，这时三段木料的表面积之和比原木料的表面积增加多少平方厘米．
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4 * 4</gadget>
<output>50.24</output>

<result>50.24</result>