The silver part of the disc is a ring, the radius of the inner circle is 2cm, and the radius of the outer circle is 6cm. What is its area?
光盘的银色部分是一个圆环，内圆半径是2cm，外圆半径是6cm．它的面积是多少？
<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">36 - 4</gadget>
<output>32</output>

<gadget id="calculator">3.14 * 32</gadget>
<output>100.48</output>

<result>100.48</result>