A rectangle and a square have the same perimeter. The length of the rectangle is 25 meters and the width is 15 meters. What is the area of the square?
一个长方形和一个正方形的周长相等．长方形的长是25米，宽15米，正方形的面积是多少？
<gadget id="calculator">25 + 15</gadget>
<output>40</output>

<gadget id="calculator">40 * 2</gadget>
<output>80</output>

<gadget id="calculator">80 / 4</gadget>
<output>20</output>

<gadget id="calculator">20 * 20</gadget>
<output>400</output>

<result>400</result>