The perimeter of a rectangular plank is 120 decimeters, and the ratio of width to length is 1:2. In order to make full use of environmental protection, it is necessary to cut the largest circle on this board. Please calculate the area of the circle as how many square decimeters?
一块长方形木板的周长是120分米，宽和长的比是1：2．为环保充分利用，需要在这块木板上截下一个最大的圆，请你计算圆的面积是多少平方分米？
<gadget id="calculator">120 / 2</gadget>
<output>60</output>

<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">60 * (1/3)</gadget>
<output>20</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<result>314</result>