There are two circles. The difference between their areas is 209 square centimeters. It is known that the ratio of the circumference of the large circle to the circumference of the small circle is 10:9. What is the area of the small circle?
有两个圆，它们的面积之差为209平方厘米，已知大圆周长与小圆周长的比为10：9，问小圆的面积是多少？
<gadget id="calculator">100 - 81</gadget>
<output>19</output>

<gadget id="calculator">209 / 19</gadget>
<output>11</output>

<gadget id="calculator">11 * 81</gadget>
<output>891</output>

<result>891</result>