The square in the western suburbs is circular. Grandpa walks around the square. It takes exactly 628 steps to walk around the square, and each step is 0.5m long. What is the area of the square?
西郊广场是圆形的，爷爷绕广场散步，走一圈正好是628步，每步长0.5m，这个广场的面积是多少？
<gadget id="calculator">0.5 * 628</gadget>
<output>314</output>

<gadget id="calculator">314 / 3.14 / 2</gadget>
<output>50</output>

<gadget id="calculator">50 ** 2</gadget>
<output>2_500</output>

<gadget id="calculator">3.14 * 2_500</gadget>
<output>7_850</output>

<result>7_850</result>