72 cm long iron wire forms a cube, what is the surface area of the cube?
72cm长的铁丝围成一个正方体，正方体的表面积是多少．
<gadget id="calculator">72 / 12</gadget>
<output>6</output>

<gadget id="calculator">6 * 6 * 6</gadget>
<output>216</output>

<result>216</result>