If a 80cm long iron wire is used to form a square, what is the area of the square in square centimetres?
把一根80cm长的铁丝围成一个正方形，这个正方形的面积是多少平方厘米
<gadget id="calculator">80 / 4</gadget>
<output>20</output>

<gadget id="calculator">20 * 20</gadget>
<output>400</output>

<result>400</result>