The radius of the inner circle of a ring is 3cm, and the width of the ring is 2cm. What is the area of the ring in cm**2.
一个环形内圆半径3cm，环宽2cm，这个环形的面积是多少cm**2．
<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

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

<gadget id="calculator">25 - 9</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

<result>50.24</result>