# How to remember trigonometry ratios

By Murray Bourne, 05 Oct 2009

I recently tweeted the following (on Twitter, of course):

Tip for remembering sin, cos and tan:Some Old Hags Can't Always Hide Their Old Age (sin = Opp/Hyp, cos = Adj/Hyp, tan = Opp/Adj)

There were several replies which I thought you may enjoy (some are a bit racey and not very politically correct - you've been warned):

**From CardsChic:** Oh Heck (sine) Another Hour (cos) Of Algebra (tan)

**From sumidiot:** From one of my students: Can A Hooker Take Off A Set Of Handcuffs?

**From wmcneary:** Some Old Hippy Caught Another Hippy Trippin' On Acid

**From tea_robot:** "Saints On High Can Always Have Tea Or Alcohol" is what I was taught!

**From LunaticNeko:** My Tip: Open a "Book of Trigonometry Problems" or something, then drill through from beginning to end. You'll remember it fast! ^ ^

**From chris_1974:** "Sex On Highways Causes Awful Havoc To Our Automobiles" is one a class once created!

See the 15 Comments below.

5 Oct 2009 at 11:21 pm [Comment permalink]

[...] cute mnemonics is fun, and the process of inventing and checking them may help reinforce the definitions, but [...]

6 Oct 2009 at 7:21 pm [Comment permalink]

And what about SOH CAH TOA? It's short, it's efficient, and it has precisely one meaning.

I know, I know, this was all meant to be on the more amusing side, but useful can be clever too, can't it?

My personal favourite, the one I *actually use* when splitting something into orthogonal components (where one component calculation involves the cos of the angle and the other involves the sin), is simply "cos is close".

"Cos is close" basically means the same thing as remembering the "CA" part of "CAH" (cos, adjacent) but it has the added benefit of rhyming. By process of elimination, if cos is used for the component that is close to the angle, sin is the other one, the opposite. SOH!

7 Oct 2010 at 2:14 pm [Comment permalink]

I would suggest," Sleep On Highway Causes Awful Harm To our Attention".

19 Apr 2011 at 5:27 am [Comment permalink]

how can i put trig ratios into a poem/song!!!

19 Apr 2011 at 12:38 pm [Comment permalink]

Hi Satish

Here's one attempt:

There are several other linked on that YouTube page.

12 Jun 2012 at 12:50 am [Comment permalink]

I'm gonna tell you how to memorise trignometric ratios faster and easier within a few minutes.

1.first step is memorise this line i.e parhle beta parhle ha ha bapu.

2. first sin = parhle/ha,i.e perpendicular/hypotenuse

follow the step above to find out rest of the ratios of trigonometry.

3.when cosec comes recipocal the lines ,then you will get the ratios.i.e ha/parhle - hypotenuse/perpendicular.

3 Jul 2012 at 3:35 pm [Comment permalink]

In Kashmir, they call the adjacent side "base" and the opposite side "perpendicular" and hypotenuse is same.

So the ratios are

sin = perp/hyp

cos = base/hyp

tan = perp/base

The rhyme they use is "Some People Have--Curly Black Hair-- To Present Beauty"

16 Nov 2012 at 7:24 pm [Comment permalink]

I always remembered it with this:

"The Old Archbishop, Sat On His, Coat And Hat!"

(T=O/A, S=O/H, C=A/H)

30 Oct 2014 at 7:59 pm [Comment permalink]

The rhyme I learnt is somewhat:

"Some people have, curly brown hair, turn permanently black"

S=P/H

C=B/H

T=P/B

8 Aug 2015 at 12:20 am [Comment permalink]

An Old Arab,Carries A Heavy,Sack Of HAy

17 Apr 2016 at 9:50 pm [Comment permalink]

Which is the best above?

20 Apr 2016 at 11:38 pm [Comment permalink]

my favourite one is...

Some Old Hippy

Caught Another Hippy

Trippin' On Acid

21 Apr 2016 at 9:45 am [Comment permalink]

That suggests you were a 60s child 🙂

23 Jan 2018 at 10:16 am [Comment permalink]

I still remember.... Some Old Hen Caught Another Hen Taking Oats Away

27 Aug 2018 at 7:22 pm [Comment permalink]

What our classes invented is "some People Have Curly Black Hair, Tinted pink-Black" its stupid but surprisingly easy to remember.

Some; sin. People: perpendicular line(opp). Have: hypotenuse.

Curly; cos. Black: base(adj). Hair: hypotenuse.

Tinted: tan. Pink: perpendicular line (opp). Black: base (adj)