Divide a circular piece of paper into several equal sectors along the radius, and then cut and assemble them into an approximate rectangle. It is known that the circumference of the rectangle is 10 cm longer than the circumference of the circle, what is the area of the circle in square centimeters?
把一个圆形纸片沿半径分成若干个相等的扇形，然后剪拼成一个近似的长方形．已知这个长方形的周长比圆的周长多10厘米，这个圆的面积是多少平方厘米？
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

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

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<result>78.5</result>