There is a circular performance in the central square with a circumference of 314 meters. If the diameter is increased by 1, how much square does the area of the table originally increase?
中广场有一个圆形表演，周长314米．现在径加1，表台的积原来增加了多少平方？
<gadget id="calculator">3.14 * 225</gadget>
<output>706.5</output>

<gadget id="calculator">706.5 - 78.5</gadget>
<output>628</output>

<result>628</result>