The circumference of the circular pool in front of the exhibition hall is 78.5 meters. What is its floor area?
展览馆门前的圆形水池周长是78.5米，它的占地面积是多少？
<gadget id="calculator">78.5 / 3.14 / 2</gadget>
<output>12.5</output>

<gadget id="calculator">12.5 ** 2</gadget>
<output>156.25</output>

<gadget id="calculator">3.14 * 156.25</gadget>
<output>490.625</output>

<result>490.625</result>