If the perimeter of a rectangle is 24 cm and the ratio of length to width is 3:1, what is the area of the rectangle in square centimeters?
一个长方形的周长是24厘米，长和宽比是3：1，这个长方形的面积是多少平方厘米．
<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">24 / 2 / 4</gadget>
<output>3</output>

<gadget id="calculator">3 * 3 * 1 * 3</gadget>
<output>27</output>

<result>27</result>