Li Hua ran around a square lawn for 80 meters. What is the area of this lawn in square meters?
李华绕着一块正方形草坪跑了一圈，跑了80米，这块草坪的面积是多少平方米？
<gadget id="calculator">80 / 4</gadget>
<output>20</output>

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

<result>400</result>