[mcv]

The Dutch version was SOSCASTOA, with a picture of a ship called the Castoa sending out an SOS because it was sinking. That picture really helped.

And I even remember what it means:

SOS: sine = opposing side divided by diagonal (schuine) side

CAS: cosine = adjacent divided by diagonal

TOA: tan = opposing divided by adjacent.

I don't think I've ever used it for anything practical, but I can still reproduce it after all this time (I'm 47 now).

[js2]

> I don't think I've ever used it for anything practical.

Just the other day I wanted to compute viewing angle and did it by hand even though there are plenty of calculators like this out there:

http://www.hometheaterengineering.com/viewingdistancecalcula...

I’d say I use it for something practical/random like that a few times a year?

Another example was placing some ceiling speakers whose tweeters had a 15° angle so that they were pointed directly at a seating position below. How far did I need to place them in front of the seating position from directly overhead.

I would guess any sort of construction you’re using it fairly often.

[dylan604]

The one that I still use is the 3-4-5 rule to ensure a right angle. Still use that one to chalk off sporting fields of play.

[mcv]

I use that one all the time, but that's Pythagoras, not sin and cos.

[dylan604]

Yeah, I know it's not the same type of math, but it's one of the few things that I still use today. To be honest, I can't think of one time in my professional career that I have needed to calculate the area under a curve to solve a life problem. Geometry has been the most used branch of math past basic arithmetic, oh, and algebra. It amazes me the number of people that don't realize how many times in a day they have solved for X.