First draw a circle with the two legs of the compass apart by 5 cm, then the leg of the compass at the center of the circle does not move, and the other leg of the compasses continues to diverge, so that the distance between the two legs of the compasses is 8 cm, and then draw a circle. What is the area of the circle in square centimetres?
先将圆规两脚叉开5厘米画一个圆，然后扎在圆心处的圆规的脚不动，将圆规的另一个脚继续叉开，使圆规两脚间的距离是8厘米再画一个圆，形成一个圆环，这个圆环的面积是多少平方厘米．
<gadget id="calculator">8 ** 2</gadget>
<output>64</output>

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

<gadget id="calculator">64 - 25</gadget>
<output>39</output>

<gadget id="calculator">3.14 * 39</gadget>
<output>122.46</output>

<result>122.46</result>