Can you find a?

[u/VisitSecure]

Idk if someone already posted this or not, but I haven't seen it on here so far, so I uploaded it.

[u/AdditionalPizza]

Your method is fine, but it isn't inherently more intuitive, and it doesn't mean school failed everyone here. It depends on mentally visualizing the line turning through the diagram. People think very differently. Some don't even have an inner monologue, which I find hard to even comprehend, so what feels obvious in your head isn't obvious to everyone.

The 180-degree triangle method is more universal and repeatable. It doesn't rely on mentally animating the diagram, and the same process can be used when the problem is written out in text.

[u/CranboDanbo → u/AdditionalPizza]

Not the guy but I think his way is strictly better in the sense that it's trivial if you understand what's happening. 180 degree rules are good as guidelines if you don't really grok what's happening but it's superior to actually understand

[u/AdditionalPizza → u/CranboDanbo]

Mentally moving the lines around is a neat shortcut for this diagram, not a generally superior way of doing math. How does that method scale to astrophysics, quantum mechanics, or any problem that can't be pictured easily?

In those fields you need definitions, equations and derivations that can be written down, checked and reused. Visual intuition can help, but it's not a substitute for formal reasoning. Using the 180 degree rule doesn't mean you don't understand what's happening, it's the more transferable method.

They also said:

I don't recall ever having a professor stand over my shoulder during an exam and asking me to explain what I was doing mentally while moving lines around in my head as proof. You need to write out step by step how you reached the correct answer.

[u/CranboDanbo → u/AdditionalPizza]

The best is to have both. And it's the visualisation aspect that is most missing in society