piece of iron wire can enclose a rectangle with a length of 12 cm and a width of 8 cm (no residue). If this wire surrounds a square, what is the area of the square in square centimeters?
一根铁丝能围成一个长12厘米，宽8厘米的长方形(无剩余)，如果用这根铁丝围城一个正方形，那么正方形的面积是多少平方厘米．
<gadget id="calculator">12 + 8</gadget>
<output>20</output>

<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<gadget id="calculator">40 / 4</gadget>
<output>10</output>

<gadget id="calculator">10 * 10</gadget>
<output>100</output>

<result>100</result>