The perimeter of a square is 100 meters. Now we want to expand the square. After the expansion, the side length of the square will be twice the current size. What is the area of the square after the expansion?
一个正方形的周长是100米，现在要扩建这个广场，扩建后广场的边长是现在的2倍，扩建后广场的面积是多少平方米？
<gadget id="calculator">100 / 4</gadget>
<output>25</output>

<gadget id="calculator">25 * 2</gadget>
<output>50</output>

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

<result>2_500</result>