The perimeter of a rectangle is 24cm, and the ratio of length to width is 3:1, what is its area in cm**2.
一个长方形的周长是24cm，长与宽的比为3：1，它的面积是多少cm**2．
<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">12 * (3/4) * 12 * (1/4)</gadget>
<output>27</output>

<result>27</result>