There seems to be a quirk in the implementation of HTML used by this forum. You can get the character ≥ in the LaTeX environment by typing \ge, \geq or (my preference) \geqslant. But if you want it in HTML, typing ≥ will not work. However, if you use the equivalent numerical character entity reference &#8805; you will get the symbol ≥.
The same applies to any other HTML character. You can get it by specifying the numerical character entity reference, but not by using the (abbreviated) name of the character. So for example ∞ won't work, but &#8734; comes out as ∞.