If the perimeter of a square is 12 cm, what is the area of the square in square centimeters?
一个正方形周长是12厘米，这个正方形面积是多少平方厘米．
<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<result>9</result>