A ring has an inner radius of 3 meters and an outer circumference of 37.68 meters. What is the area of the ring in square meters?
一个环形，内圆半径是3米，外圆周长是37.68米，这个环形的面积是多少平方米．
<gadget id="calculator">37.68 / 3.14 / 2</gadget>
<output>6</output>

<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

<gadget id="calculator">3.14 * 36</gadget>
<output>113.04</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<gadget id="calculator">113.04 - 28.26</gadget>
<output>84.78</output>

<result>84.78</result>