A piece of square glass is cut off by 8 cm on one side and 12 cm on the other side. The area of the remaining rectangular glass is 904 cm2 less than the area of the original square glass. What is the side length of the original square in cm?
一块正方形玻璃，一边截去8厘米，另一边截去12厘米，剩下的长方形玻璃的面积比原来正方形玻璃的面积少904平方厘米，原来正方形的边长是多少厘米．
<gadget id="calculator">12 * 8</gadget>
<output>96</output>

<gadget id="calculator">904 + 96</gadget>
<output>1_000</output>

<gadget id="calculator">12 + 8</gadget>
<output>20</output>

<gadget id="calculator">1_000 / 20</gadget>
<output>50</output>

<result>50</result>