What is the maximum area of a rectangle surrounded by 10 meters long wire?
用10米长的铁丝围成的长方形的面积最大是多少平方米．
<gadget id="calculator">10 / 4</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">(5/2) * (5/2)</gadget>
<output>25/4 = around 6.25</output>

<result>25/4 = around 6.25</result>