Xiao Ming’s family has a cylinder of wood. If it is sawn vertically along the diameter of the bottom surface, the surface area will increase by 50 square decimeters compared to the original one. What is the side area of this cylinder of wood?
小明家有一根圆柱体木料，如果沿底面直径把它垂直锯开，这样表面积比原来增加了50平方分米，请问这根圆柱木料的侧面积是多少平方分米？
<gadget id="calculator">50 / 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<result>78.5</result>