The radius ratio of the small circle to the large circle is 3:5, the circumference of the large circle is 31.4dm longer than the circumference of the small circle, how many decimeters is the circumference of the small circle?
小圆与大圆的半径比是3：5，大圆的周长比小圆的周长长31.4dm，小圆的周长是多少分米？
<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<gadget id="calculator">31.4 / 2</gadget>
<output>15.7</output>

<gadget id="calculator">15.7 * 3</gadget>
<output>47.1</output>

<result>47.1</result>