If the perimeter of a square is 36 centimeters, what is its area in square centimetres?
一个正方形的周长是36厘米，它的面积是多少平方厘米．
<gadget id="calculator">36 / 4</gadget>
<output>9</output>

<gadget id="calculator">9 * 9</gadget>
<output>81</output>

<result>81</result>