A circle, the radius of the larger circle is 5 cm, and the radius of the smaller circle is 3 cm, find the area of the circle.
一个环形，大圆半径为5厘米，小圆半径为3厘米，求环形的面积．
<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>