The diameter of the inner circle of a circle is 6 cm and the radius of the outer circle is 10 cm. What is the area of the circle in square centimetres?
一个圆环的内圆直径是6厘米，外圆半径是10厘米，这个圆环的面积是多少平方厘米．
<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

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

<gadget id="calculator">100 - 9</gadget>
<output>91</output>

<gadget id="calculator">3.14 * 91</gadget>
<output>285.74</output>

<result>285.74</result>