The radius of the outer circle of a circle is 10cm, and the diameter of the inner circle is 16cm. What is the area of the circle in cm**2.
一个圆环的外圆半径是10cm，内圆直径是16cm，这个圆环的面积是多少cm**2．
<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<gadget id="calculator">16 / 2</gadget>
<output>8</output>

<gadget id="calculator">8 ** 2</gadget>
<output>64</output>

<gadget id="calculator">3.14 * 64</gadget>
<output>200.96</output>

<gadget id="calculator">314 - 200.96</gadget>
<output>113.04</output>

<result>113.04</result>