Divide a circle into several equal parts and assemble them into an approximate rectangle. The circumference of the rectangle is 8 cm longer than the circumference of the circle. What is the area of the circle in square centimeters?
把一个圆平均分成若干份，拼成一个近似的长方形，拼成的长方形的周长比圆的周长多8厘米，这个圆的面积是多少平方厘米．
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

<result>50.24</result>