If a cylindrical wood with a base radius of 2 decimeters and a height of 5 decimeters is cut into two equal halves along the diameter of the base, the surface area is increased by how many square decimeters.
把一个底面半径是2分米、高5分米的圆柱形木料沿其底面直径切成相等的两半，表面积增加了多少平方分米．
<gadget id="calculator">2 * 2 * 5 * 2</gadget>
<output>40</output>

<result>40</result>