Is there a way to enter an equation as an option in the multiple dropdown in classic quizzes? I need to use line segments and congruent symbols, and I cannot do that with just a textbox.
No, this functionality does not currently exist.
You can use Unicode, which has a congruent symbol, but that won't help with the line segments. Here is a list of some Unicode symbols that you can copy/paste: Unicode/List of useful symbols - Wikibooks, open books for an open world
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