After a piece of cylindrical wood with a length of 2m is cut into two sections, the surface area increases by 25.12dm**2. What is the area of the bottom of this piece of wood in dm**2.
一段长2m的圆柱形木材，把它横截成2段后，表面积比原来增加了25.12dm**2．这根木材的底面积是多少dm**2．
<gadget id="calculator">25.12 / 2</gadget>
<output>12.56</output>

<result>12.56</result>