If the length of a rectangular frame is 12 cm and the width is 8 cm, what is the area of the square equal to its perimeter?
一个长方形框架的长是12厘米，宽是8厘米，和它周长相等的正方形的面积是多少．
<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>