rectangle and a square have the same perimeter. It is known that the length of the rectangle is 20 decimeters and the width is 12 decimeters. What is the area of the square in square decimeters?
一个长方形和一个正方形周长相等，已知长方形长20分米，宽12分米，求正方形的面积是多少平方分米？
<gadget id="calculator">20 + 12</gadget>
<output>32</output>

<gadget id="calculator">32 * 2</gadget>
<output>64</output>

<gadget id="calculator">64 / 4</gadget>
<output>16</output>

<gadget id="calculator">16 * 16</gadget>
<output>256</output>

<result>256</result>