The perimeter of a rectangle is 30 cm, and the ratio of length to width is 3:2, what is the area in square centimeters?
一个长方形周长是30厘米，长与宽的比是3：2，面积是多少平方厘米？
<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">30 / 2 / 5</gadget>
<output>3</output>

<gadget id="calculator">3 * 2 * 3 * 3</gadget>
<output>54</output>

<result>54</result>