In the following figure, AF is the perpendicular bisector of DN. What is the measure of angle CDT?

If this is drawn proportional to scale, it would be C. Also, I remember there is a thereom to solve this, but I'm sorry I forgot.

If  AF is the perpendicular bisector of DN then DF  =  NF

So...by  side-angle-side.....triangles DFA  and NFA  are congruent

And angle  ADF  = angle ANF   = 55°

But angle CDT  is a vertical angle to angle ADF....so it must also measure 55°