A cylindrical wood with a length of 2 meters and a cross-sectional radius of 1 decimeter is cut into 4 sections of the same length, and the surface area is increased by how many square decimeters compared with the original.
一根长2米，横截面半径为1分米的圆柱形木料截成同样长的4段，表面积比原来增加多少平方分米．
<gadget id="calculator">1 ** 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 1 * 6</gadget>
<output>18.84</output>

<result>18.84</result>