I believe it's the = equal sign with a little ~ squiggly on top of that.
Answer:
[tex]\cong[/tex]
Step-by-step explanation:
Congruent angles are marked with a [tex]/[/tex] or noted in an equation as [tex]\cong[/tex].
[tex]\angle 4 \cong \angle 6\\\text{Ange 4 is congruent to angle 6}[/tex]
