What is the side length of a square surrounded by a 1 meter long rope?
用一条1米长的绳子围成一个正方形，这个正方形的边长是多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>