A cuboid, the bottom surface is a square with a perimeter of 12 cm, and the sides are also a square when unfolded. What is the surface area of this cuboid?
一个长方体，底面是一个周长为12厘米的正方形，侧面展开后也是一个正方形，这个长方体的表面积是多少平方厘米？
<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<gadget id="calculator">3 * 3 * 2</gadget>
<output>18</output>

<gadget id="calculator">12 * 12</gadget>
<output>144</output>

<gadget id="calculator">18 + 144</gadget>
<output>162</output>

<result>162</result>