If a cylindrical steel is cut into three sections along the direction parallel to the bottom surface, the sum of the surface areas is increased by 12 square centimeters, what is the bottom area of the steel in square centimeters?
把一根圆柱形的钢材沿平行底面的方向截成三段，表面积之和增加12平方厘米，钢材的底面积应是多少平方厘米．
<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<result>3</result>