The ratio of length to width of a rectangle is 2:3, its perimeter is 30 meters, what is its area?
一块长方形地长与宽的比是2：3，它的周长是30米，它的面积是多少．
<gadget id="calculator">2 + 3</gadget>
<output>5</output>

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

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

<result>54</result>