If a cuboid is cut into two smaller cuboids on average, the surface area increases by 40 square centimeters. What is the cross-sectional area of the cuboid in square centimeters?
将一个长方体平均切割成两个小长方体表面积增加了40平方厘米，这个长方体的横截面积是多少平方厘米．
<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<result>20</result>