What is the area of a square with a perimeter of 16 cm
周长是16厘米的正方形，它的面积是多少平方厘米
<gadget id="calculator">16 / 4</gadget>
<output>4</output>

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<result>16</result>