The perimeter of a rectangle is 80 meters, and the ratio of length to width is 3:1. What is the area of the land in square meters?
一个长方形地的周长是80米，长与宽的比是3：1．这块地的面积是多少平方米？
<gadget id="calculator">80 / 2</gadget>
<output>40</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">40 * (3/4)</gadget>
<output>30</output>

<gadget id="calculator">40 - 30</gadget>
<output>10</output>

<gadget id="calculator">30 * 10</gadget>
<output>300</output>

<result>300</result>