The perimeter of a rectangular piece of land is 120 meters. It is known that the ratio of length to width is 3:1. What is the area of this piece of land in square meters?
一块长方形地的周长是120米，已知长和宽的比是3：1，这块地的面积是多少平方米．
<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">120 / 2 / 4</gadget>
<output>15</output>

<gadget id="calculator">3 * 15</gadget>
<output>45</output>

<gadget id="calculator">45 * 15</gadget>
<output>675</output>

<result>675</result>