Input power with PF, impedance on transmission line and transformer
The answer to the second half of your question is definitely just to divide the impedance on the line side by 16^2, because the equivalent impedance ratio is the square of the transformer ratio, as described here:http://www.radioremembered.org/outimp.htm

For the first half they have effectively told you the magnitude of the answer (239kV) but not the phase angle.
Using phasors:
v_out=v_in-I*R

You know the phasor for the current.
Graphically, R is a 45deg phasor, whose length varies with distance. Multiplying phasors adds angles, and the negative sign is a 180 deg phase shift, so you need to add 225 to the current angle to get the direction of the voltage drop phasor. (I.e. 257deg or 193 deg, I'm not sure if your current is leading or lagging, I forget the convention). Then you just need to solve for the multiplier to get a result vector of the appropriate length.