These questions on using SohCahToa can seem a little daunting.. but they are used extensively in maths and have some real, practical applications.
Watch the video and try the quick test.
You can use SohCahToa – the “trigonometric functions”
- to find the size of an angle in a right angle triangle or
- to find the length of a side in a right angle triangle (more about this in the next post)
To find the size of an angle you need to know the lengths of two of the sides.
The sides are then labelled relative to the angle you need to find – in other words, ‘opposite’ is opposite. So:
A typical exam question would be something like:
“Calculate the size of angle x in this right angle triangle. Give your answer correct to 3 significant figures’
With these type of questions it’s better to have a series of steps:
- label the side opposite to the angle
- label the hypotenuse (longest side)
- label the adjacent
- decide which ratio from SohCahToa – in this question we are going to use Toa
- make sure the calculator is in degree mode (look for D symbol on your display)
- Use the inverse trigonometric function (on a scientific calculator use the SHIFT key to access)
Trigonometry is an really useful part of maths and is used in architecture, building and all sorts of construction. From finding the heights of trees, towers or ocean tides to navigation, physics and astronomy – you’ll find some trigonometry.
Did you know that the ‘trig’ bit means ‘triangle’ and the ‘metry’ bit means ‘measure?!’
Watch the videos on YouTube:
How to find the missing angle in a right angle triangle
Click here to try the Quick Test SohCahToa
There is a typo on your page under Trigonometric Ratios above; Tan = TOA not TOH,
Thanks for your excellent lessons, really appreciate them
Ah. OK – will change.
Hypotenuse
do you need the minus one for cosine and sine?
when he teaches better than your school teacher
ok you did not explain why you had to use the inverse… this will confuse
a lot of people
thanks it helped me so much
THANK YOU!!!!!!!
Thanks For Helping me understand trigonometry! no teacher is better than
you
your students are lucky +Simon Deacon
Subscribed Aswell
Thank you so much for the help and am sure I will be using these videos
again for a-level
Thank you, this helped so much
bruh I need this for my final tmw
Thanks this helped a lot
Question… This bothers me that I don’t quite understand it but, Why is it
that when I type Cos-1(3.9/4.7) it comes up with 0.592069997?
thank you so much
Thank you:)
In America, the spelling is “hypotenuse” but I don’t know what it is in
England 🙂
Thanks this will help me with some last minute homework.
Hi there how come when I type in sin-1(3/2) it comes up with maths error?
thanks for actually teaching me, my teacher sucks
thanks, great, u helped me so much with my maths notes
Thank you, You are very helpful!
thank you this helped me so much 🙂
How is it that you know what’s the opposite located?
This video was so helpful! I’m definitely subscribing and will surely be
back for more!
Very clear! Helped my revision massively, thanks! 🙂
Have a Math Test tomorrow and was feeling confused about the topic. You
helped clarify things!! Quick question, am i supposed to put (-1) after
which ever one i use for example Sin(-1)?
Thank you, this was a nice refresher to help me with my homework. I really
appreciate what teachers like you do when you make these videos, they are
extremely nice when others like myself may need some help or a reminder on
how to do something on short notice. Thanks to you we have a teacher in our
pocket now!
Brilliant nice one
Thanks! This was really helpful. I have my final exam tomorrow. Subscribed
^_^
Thanks your teaching helps alot
Thanks for your help. When do you use the inverse trigonometry? E.g. tan-1
or for sin or cos? Thanks again
Thanks, helped refresh my memory for my ACT practice! 😀
thx this will really help me tomorrow for my maths test 🙂
This was a really helpful video thank you! I’ve been sent through
accelerated Math/Calculus since I was about 7 and we’ve only realized now
that I missed out the entirety of SOHCAHTOA…. and I’m in my last year of
school 🙂 So thanks for the help
Thankyou!!!!!!! I went from zero knowledge to full on I know what I’m
doing! Thankyou very much!!!
thank’s for this video it really helped a lot with me missing class
I know how to do trigonometry now +Simon Deacon
Subscribed:) watching your videos are really helping me with my maths gcse.
Thanks!!
Thank You!!!
Thanks! Great Help
This helped me cram right before my ACT test. Thanks!
I don’t get it
Thank you so much! I had missed a whole week of my geometry classes and now
it all makes so much more sense!
Thanks skrub lord
lovely sir but i dnt really understand this sohcah, pls wht can i do thanks
hi , I done exactly what u said and ended up with a different answer which
was 37.69234667 – 37.7 +Simon Deacon
very good
At first I didn’t understand it but after 30 minutes i realised just how
simple it is!
Thanks I needed to learn this for my placement test
hi im having a problem when i type in cos(3.9/4/7) on my calculator it
comes up as .99? why?
can you use any of the three different things the same way?… the SOH,
CAH, TOA so for instance if i only had the opposite length and the
hypotenuse length would i use “SOH” in the same way as “CAH” (Using the sin
and sin-1 button on my calculator..)
I’m a bit confused how to know when to use to the power of -1 or not for
sin, cos and tan. Do you something basic to explain it?
Thanks
Thanks I forgot to put it to power of -1
Thanks bro, you have been really helpful. Like your teaching strategy!!!
Amazing help. Thank you so much.
Thankyou, I was really worried about my exams but you have cleared this up
for me
Thanks so much. This was so helpful to me. The way my teacher showed me was
a little more complicated. This hit it right out the park.
Thankyou best this was explained very well much better than my math teacher
did I thought I was going to fail my test. Thankyou!
Thank you. Really clear and helpful
You are a saviour
Thanks so much because I was stuck on my geometry!
You’re seriously so helpful. Thank you so much! Ive also subscribed to you!
😀
Simon deacon is god
really helpful thks
Are you a math teacher?
hello. i have a question..
A 10-pound object is suspended by a string from an overhead support. A
horizontal force of 5.8 pounds is applied on the object. The measure of the
angle which the string makes with the horizontal is??
a. 30 degree
b. 45 degree
c. 60 degree
d. 90 degree
the answer is 30 degree..
but I don’t know the solution. help? 🙂
thanks in advance!
hello. i have a question..
A 10-pound object is suspended by a string from an overhead support. A
horizontal force of 5.8 pounds is applied on the object. The measure of the
angle which the string makes with the horizontal is??
a. 30 degree
b. 45 degree
c. 60 degree
d. 90 degree
the answer is 30 degree..
but I don’t know the solution. help? 🙂
thanks in advance!
thanks!
Did you make your website ???? If yes could you possibly upload some C# or
C++ or game maker scripting if possible
Thanks
Thank you
Hi Simon,
Thank you for this video but when I typed in cos-1(3.9/4.7) I ended up
with .592069997… What did I do wrong?
thanks bro this really helped
A brilliant refresher for me thanks!
can you be my teacher 😀
Thank you sir, this was helpful
Is it just me or are videos online a trillion times better than teachers?
Thanks Simon!!!
Excuse me Simon, why do i get Syntax Error? Is there any other way to solve
that?
Thanks Simon for another great video. Would I still get the same answer if
I accidentally left out the brackets that you did in 7:01?
have i got this right if the angle is attached to the hypotenuse and
adjacent its cos if attached to the opposite and hypotenuse its sin and
opposite and adjacent its tan
i remember it by the side the angle is attached to is the 1 you use
Thank you so much ! By the way, you always use the -1 to calculate angles ?
Thanks again ! Finals tomorrow so this will help.
does SOHCAHTOA only apply to right triangles?
Thank you this helped a lot.
Thanks for the help! Very easy to understand now, thanks.
Nice and
quite helpful thnx xD
im trying learn trig in 3d
My calculator sucks balls
Thanking you for my top marks in my Math exam!!
i dont understand where the minus 1 comes from
what if your only given the value of 1 side
i remember it as cos angle is attached to adjacent and hypotenuse sin is
hypotenuse attached to opposite and tan adjacent attached to opposite
even though your videos help me a lot there is one concept of math science
called pre-calculas sorry if i spelled it wrong, but you should think about
making a video on that thanks anyway! 🙂
Thanks so much for this video! It helped me out a lot!
hypotenuse doesn’t matter we’re in a math class not a grammar 🙂 very
helpful thank you
very helpul video
hypotenuse
Hey , so its tan1 divided by 5/6 then thats how you get your answer?
i dont know y its so different into my computations? instead of 39.805
should the right answer the answer on my calcu is 1.100 please help me..
Why did you use the (tan -1) instead of the regular tan?
Thank you so much got an exam tommorow and i think this is very useful
Thanks Simon really helped
OMG thanks soooooo much I have a huge exam and this is a small part in it
but was also the part I have no clue about! Thanks so much, you make so
much more sense than my teacher 😀
Great video! It helped me immensely! thank you so much
Really helpful video! Thank you very much!
Simon I don’t know if you will ever respond to this comment ever even look
at it but I won’t you to know that you may have double handily saved my
mark on the test and i wan’t to make love to you!
Thankyou! Really helped xx
The spelling is hypotenuse, not hypoteneuse.
Hypotenuse, just like it sounds.
Thank you! GCSE maths revision is hard but your videos make it really
simple!
my only question here is that I though that when you are trying to find the
ANGLE in the Triangle why did you not do SHIFT 4.9 Divided by 4.7?? thats
at least how i Learned to find the Angle, cus I thought that if you dont do
the SHIFT on the calculator first then it wont give you the complete answer
to the Angle.. lol, I live abroad and Im in 11th Grade, I learnt this at
the beginning of my school year and now im just Reviewing it over and over,
and i wanted to check online if other people Calculate this like me..
You’re good but the video cam is somehow blur…I can’t see the exact words
or numbers…but thanks you’re great!!!
Please like and leave a comment!
Visit https://www.3minutemaths.co.uk for real maths, tips and techniques.
Thanks man great help
There has to be some way you could possibly find this info without a
calculator.
thanks a lot!
Thanks for your help!
but good video mate thanks for helping with me homework
You spelt it wrong its Hypotenuse not Hypoteneuse lol
I got .694738 what did I do wrong?
Thank you so much, this video helped a LOT! 🙂
how did you calculate 10 times sin 40 degrees using the scientific cal.
which button to use. Thanks
which calculator do you have? on most you can use shift then cosine button for cos-1 if thats what your looking for…but google is your friend for how to use a calculator
one angle is right so it is 90 degrees. so if you can find one of the other two using trig then the last angle is simply found by adding up the sum of the two angles(90+ x ) and then subtracting by 180.
Please post, pin, tweet, like or subscribe!
Please post, pin, tweet, like or subscribe!
That’s great and glad to help 🙂
Awesome video! Very helpful. Thank you 🙂
What if the you need to find two angles?
nice u just explained how to use calculator impressive
Thank you! Very helpful 🙂
YOU ARE SUCH A NICE MAN! HAVE A NICE DAY 😀
Hi – the symbol you’re looking for is cos-1. My calculator shows it in orange print and I need to press shift first. Hope this helps and thanks for the comment. Rgds S
How do you cosine to the power of negative 1 on a calculator ?
If anyone’s tripping up with the wrong degree thing, check your calculator’s settings. It might be on “radian” instead of “degree.” That’s why mine messed up on this also.
Hi – some calculators use different notation but you’re looking for Tan-1. This is the inverse of Tan and, on my calculator it’s printed in yellow. My buttons are Shift Tan – this gives me Tan-1 (
I then type 5 / 6 and close the bracket.
My display reads Tan-1(5/6). When I press the = I get 39.805…
I hope this helps and all best with the ACT!
Rgds S
I’m pushing buttons 2nd, TAN, (5/6) but it equals .6947382762. Please help!! I have the ACT tomorrow!!!
Great video! You really helped me! thanks 😀
Thank you. Very helpful 🙂
You explained this better than my teacher, thank you!
thank you so much man saved my life once again
That’s great – thanks for letting me know 🙂
Thank you that helped a lot
So helpful for my exam! Thanks so much
That’s great – thanks for the comment 🙂
this really helped to get sohcahtoa clear in my head:))) thankyou!
Sorry.. no.. we’re doing a lot of GCSE (same as Regents?) revision so lack of time. Good luck with your finals!
Did you make the video yet? I have finals tomorrow. Integrated algebra. :$
I subscribed
Will do – I’ll let you know when done. All best with your studies. S
Oh and can you do a video on how to simplify radical expression and adding radicals
Ohhhh thanks! I have regents coming up next week. Do you know any topics that always reappear on the regents?
Hi – hypotenuse is always the long side. The adjacent is next to the angle you are working on. Its always good to re label the diagram each time, so hopefully not too confusing 🙂
So how do we know whats the hypostnuse and whats the adjacent angle?
Thanks so much.
Thanks, the video was very helpful and made trigonometry incredibly easy to understand.
can you make a video showing how to use the calculator when you are doing this because i cant get out the answer
Thanks Sammie – I’ll try to remember 🙂
hypotenuse
Hi John –
The number you’ve got is the tan value.
Calculators keys can be a little different, but try this: Shift, Tan, (5/6). Sometimes the command to get tan to the power of minus one is printed on the key in orange.
Hope this helps and let me know how you get on.
All best
S
why it is always wrong answer when i press tan-1(5/6)? the answer is always 0.014545436094.. i didnt know what value i type..
why it is always wrong answer show in my calculator? it show the answer 0.014545436094 if u press tan-1 (5/6)?
Hi – no prob and good luck with the exams
thanks man this is just what i need to help me understand trigonometry for my summer exams. ur a life saver man thanks 😉
That’s great and thanks for your comment. Good luck with the job! 🙂
Just wanted to thank you for posting your very informative videos . I needed to relearn a lot of basic math for a job placement test and thanks to your lessons I passed with no troubles .