When deriving the method of calculating the area of a circle, after Xiaohong cuts a circle into an approximate rectangle, the circumference increases by 3 decimeters. What is the area of the circle in square centimeters?
在推导圆的面积计算方法时，小红将一个圆切拼成近似长方形后，周长增加了3分米，圆的面积是多少平方厘米．
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">15 ** 2</gadget>
<output>225</output>

<gadget id="calculator">3.14 * 225</gadget>
<output>706.5</output>

<result>706.5</result>