If a cylindrical steel is cut into two sections, the surface area increases by 6 square decimeters. If it is cut along the diameter, the surface area increases by 10 square decimeters. What is the original surface area of this steel?
一根圆柱形钢材，截成2段，表面积增加6平方分米，如果沿着直径截，表面积增加10平方分米，原来这根钢材的表面积是多少？
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">3.14 * 5</gadget>
<output>15.7</output>

<gadget id="calculator">6 + 15.7</gadget>
<output>21.7</output>

<result>21.7</result>