A rectangular piece of paper has a circumference of 140 cm and a ratio of length to width of 4:3. If you cut out the largest circular piece of paper, what is the area of this circular piece of paper in square centimeters?
一张长方形的纸片，周长是140厘米，长和宽的比是4：3．如果用剪成一个最大的圆形纸片，这张圆形纸片的面积是多少平方厘米？
<gadget id="calculator">140 / 2</gadget>
<output>70</output>

<gadget id="calculator">4 + 3</gadget>
<output>7</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">70 * (3/7)</gadget>
<output>30</output>

<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">15 ** 2</gadget>
<output>225</output>

<gadget id="calculator">3.14 * 225</gadget>
<output>706.5</output>

<result>706.5</result>