how do you measure angles/ratios properly? at what angle? what type of pictures?

[Balkansandsh]

lots of people use selfies to measure angles and ratios, I use photoshop but I find that they vary heavily based on angle and photo. Now I'm under the impression to measure your angles/ratios correctly you need one of those photoshoot pics like all the models have. I'd love to be wrong because that would require so much more effort. but I guess nothing is easy haha.
example of "photoshoot pics"

 

[Balkansandsh]

^ in ps ive gotten 109 for my genial angle in a picture and 140 in another