If a cylindrical stick with a base radius of 2 cm is cut into two pieces, the surface area is increased by how many square centimeters.
把一个底面半径是2厘米的圆柱形木棍截成两段，表面积增加了多少平方厘米．
<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>