How to use SohcahToa with a right angle triangle to find a missing length

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You can use the trigonometric SohCahToa ratios to find the length of a missing side in a right angle triangle. You need to know the length of another side and the size of one of the acute angles.

[@physicsimpossible73]

I liked your construction example, it helps people appreciate that this stuff is actually useful in real life as a lot of people in my classes don't appreciate maths and think it's a waste of time :(

[@3minutemaths]

Thanks Epicnerd73 glad the video helped :-)

[@gazsutton1272]

Finally a description that makes sense, thanks.

[@3minutemaths]

+gaz sutton - that's great and glad to help :-)

[@derickporter8381]

gaz sutton is

[@orcguy2380]

Thank you so much you have just clarified the part i was stuck on.

[@3minutemaths]

Hi - thanks for the question. The way SohCahToa works is with the relationship between the angle and the sides. The problem is the opposite and adjacent will change depending upon which angle you're using. With these sorts of problems it's probably better to label what you know, then work out if they are opp, adj or hyp, and then go from there. I hope this helps. All best S

[@XDinaChowX]

OMG this was soooooooooooooo helpful! I'm found GCSE maths and I had no idea how to do this trigonometry SOHCAHTOA thing! This video really really really helped! Thanks so much!! :

[@theresevining4786]

Hi! I'm just starting Trigonometry and this was one of the first things we've been going over... I had trouble in class understanding it, but this video helped a little. I'm sure that I'll eventually get the hang of it. Thanks!

[@3minutemaths]

+Therese Vining - Glad to help and all very best with your studies! :-)

[@EvMeister]

This really helped me out, thanks a lot man!

[@3minutemaths]

Glad to help and all best S :-)

[@chriscaraway6490]

You teach it so much better than my teacher does. Thank you 👍🏻

[@larakitney3981]

I love your math tutorials: simple, clear, understandable and helpful! keep it up, thanks

[@3minutemaths]

Glad to help and all best S :-)

[@JAM609]

Very helpful, thank you. Now I'm just looking for when you use Cos or Tan to find either the hypotenuse or adjacent. Also solving for when one side is labeled "X" or "X+2". Knowing the difference between adj and Opp and knowing when or how to use it.

[@nanayaa7179]

i have never done SOHCAHTOA and this was very helpful.you made it easy for me,thank you

[@3minutemaths]

Glad to help and all best :-)

[@3minutemaths]

Hi - sounds like you might need to use Area = 1/2abSinC. Use this to find the length of b although you'll need to change the equation around a little bit. I haven't got a video for this but there's quite a few on KZbin. I hope this helps. Best S

[@stealth1546]

I really appreciate this, especially that I missed some things in high school. Really cleared things up.

[@3minutemaths]

+stealth1546 - That's great and really glad to help :-)

[@lorizaitz6928]

(I'm using my moms youtube right now) omg thank youuuuu! your video saved my math final grade! and just to let you know, there is an extremely high pitched feedback your mike gets when you talk, I just thought you should know. Thank youuuuu!!

[@3minutemaths]

Hi Lori Zaitz glad the video helped :-) Got a new camera so should be better sound now !

[@3minutemaths]

Keep working through questions and you'll be fine. All best S

[@3minutemaths]

Please like and leave a comment! Visit www.mathswrap.co.uk for real maths, tips and techniques.

[@KatelynNicole226]

Thank you SO much I missed a day of class and I used this video to catch my self back up! 😊

[@3minutemaths]

Glad to help KatelynNicole226 :-)

[@VioletViolence]

I struggled so much with this but you helped me so thank you :)

[@breadfishinc]

Thank you so much, this was the only area of trig that I wasn't too sure about, even though I did know how to do non-right angled trig

[@3minutemaths]

Glad it helped :-)

[@andynguyen110]

Thank you for your great explanation. This really helped me out a lot!

[@thomasrussell6664]

Actually helped me a lot with GCSE mock exam ... Thanks! :)

[@3minutemaths]

That's great Thomas Russell and glad to help :-)

[@callofdutyguy95]

Thanks for the help !!!!! I needed to remember this for my exams !

[@3minutemaths]

Gianluca Spagnuolo Glad to help and all best for your exam :-)

[@3minutemaths]

Hi yes Cah would work fine if you had the hypotenuse and the angle ...make sure it's the one adjacent to the adjacent side you are working out. (Hope that makes sense :-). All best S

[@tris8312]

My math teacher taught me but i forgotten the technique. Thank you for reminding me the technique :).

[@3minutemaths]

Hi Russell - yes, the concept is still the same. You need to know one angle and one side to find another length ... sometimes there's a bit of calculation first to get all the info you need.

[@3minutemaths]

Hi - yes, you need to use the inverse on a calculator to find angles.

[@XxRisinInfernoxX]

Thanks, wouldn't have done my math project without you :-).

[@3minutemaths]

Glad it helped :-)

[@mr.j5800]

I'm studying for finals and this helped a ton! Thanks😘

[@3minutemaths]

+Jonatan Sabillon - Glad to help and all best S :-)

[@3minutemaths]

Hi - I think that your calculator is set to degrees rather than radians. (Radians are a different way of measuring an angle and some calculators will allow you to work with either). All best S

[@lukeheikkinen4882]

Thank you so much man helped me with my math assignment

[@tatendamashiri2713]

I was so much helped with your explanation.

[@edenharper9573]

This was so helpful! Thank you so much!

[@OfficialAlRich]

Can I just say your really helpful honesty really good thank you

[@hadifarrukh6274]

fanatastic explanation. you are an immpecable tutor to say the least.

[@3minutemaths]

Thanks hadi farrukh glad to help :-)

[@janeciagraham8647]

U help me alot I got 98% on my exam thank u so much

[@3minutemaths]

Hi Zain - you'll need to know either the length of an adjacent side or the angle to use SohCahToa. If you send me the question (through MathsWrap if easier) I'll will be happy to help :-) All best S

[@mariekeane4482]

Really helpful..best wishes a mature student

[@KabzOG]

Your maths videos are so helpful! But may i ask, if you have another length of the hypotenuse, such as 6. So it is is Opposite/6, what would you times it by? Would it be 6?

[@3minutemaths]

Hi - yes, that's correct :-)

[@3minutemaths]

That's great - glad it helped and thanks for letting me know :-)

[@NiazFilms]

if im given a right angle triangle which asks me to find the missing side in my question the hypotenuse do i use the same method that you did except with cosine in this case?

[@Starpilot149]

This really helps man, thanks.

[@3minutemaths]

Glad to help Starpilot149 :-)

[@MrWHEELZZz]

do you only inversese sin cos or tan when your finding the angle inside?

[@Photaosynthesis]

Thank you, that helped me a lot!

[@stephenbarker100]

how do you know if you have to divide or multiply

[@-MrMazw-]

thank you for your help I really appreciate it

[@alfred3299]

If im given one angle, one side and the area, how to do i find the rest? (its a scalene triangle)

[@70carlton]

Thank you so much Simon very helpful.

[@3minutemaths]

Glad to help 70carlton . All best S

[@ItsJustBrendan]

U are an enormous life savor thank you so much

[@3minutemaths]

+Brendan Banayan - Glad to help :-)

[@bridgetcanavan9328]

Thanks this is a really helpful video!!! I get it now! :)

[@kimfoster7280]

makes a lot of sense thank you!

[@Wiseguy248]

You only multiply the Numerator. But say if I don't have my Hypo, but rather the Adjacent? Is the the concept still the same? Probably, but what do I do if I have Denominator? Dividing is probably my choice...which I have a difficulty on how to do that. lol

[@zv3000]

Hi got a question probably a bit impossible to work out but what if the information you have is just the adj and opp besides obviously the 90* ? imagine the adj is 53.34 cm and the opp is 10.16 ?

[@3minutemaths]

Hi You could use Tan - this will calculate the angle, as you know the opp and the adj. If you are looking for the length of the hypotenuse then Pythagorus is probably better kzbin.info/www/bejne/Z56bqYWFlrKNp7s . I hope this helps and thanks for the comment. All best S

[@LazymonkeyIndustries]

Thank you very much for this tutorial sir . It's very helpful especially for my upcoming finals :P

[@3minutemaths]

That's great and good luck with your finals :-)

[@LazymonkeyIndustries]

Simon Deacon Thank you :)

[@3minutemaths]

Great - thanks for letting me know :-)

[@robinrene6179]

thanks for helping me pass my math test

[@3minutemaths]

+Robin Kerr Glad to help and congratulations!

[@AveryEngstrom]

what about finding the exact value rather than the approximate decimal? would it just be the base of 10*sin(40) or is there a way to simplify it further?

[@3minutemaths]

Hi - you're right and 10sin(40) is fine - although most exams will ask for the decimal equivalent, usually to 1dp or 3 sig fig. Best S :-)

[@mdeleon97md]

Really helpful video!!!!!

[@gabriellagomez5664]

thank you so much this was extremely helpful

[@3minutemaths]

That's great Gabriella Gomez and glad to help :-)

[@seanspicer3021]

Thanks for the help!

[@3minutemaths]

Alex White Welcome and glad the video helped :-)

[@jasn5754]

I posted a question on one of your other videos. Building things, I usually know two desired angles and either O or A. Hardly ever (if ever) known the Hypotenuse as it's normally the value I'm trying to find. Usually know angle a, b, and length O or A. Can you tell me what I need to remember for this? ie. I have a support that connects at 1800mm high, set out at an angle of 15º from vertical. So how far out will it be when it reaches the floor? a=15 b=90 c=75 O=1800 A=? H=?

[@3minutemaths]

Hi Jåsøn ß OK ... if I understand this correctly I'm imaging a roof and you want to know the length of the slope. The pitch is 15 degrees and it reaches 1800mm at the highest point. Probably the easiest way is to find the length AB and then use Pythagorus to calculate the hypotenuse. So to find AB use Tan = Opp / adj Tan 75 = AB / 1800 Tan 75 x 1800 = AB So AB = 6717.7mm (big roof !) Now I know the height is 1800 and the length is 6717.7mm .... use Pythagorus to find the slope length (hyp) so: Hypsquared = heightsquared + lengthsquared Hyp = square root of (1800squared + 6717.7squared) Hyp (slope length) is 6954.67mm Is this OK? Here's a playlist for Pythagorus kzbin.info/aero/PLPglScc3TJ-P1UlIBsXNB5xIl34OtN5qg All best S :-)

[@jasn5754]

Simon Deacon Thanks for replying Simon. I think the figures are the reverse though? 15º from vertical (90) Would that mean the pitch is 75 degrees. It's not a roof, which might've mislead things a bit. TAN (15) = AB / 1800 (height)? Be great to properly understand the relationship between angle (a) and the Adjacent side, when you know what the height is (Opposite side)

[@3minutemaths]

Jåsøn ß Hi ... yes, it's a little difficult to type questions / responses on KZbin comments. I'm always around for a helpout if you'd like to chat through the subject. All best S

[@junk77yt]

this helped a lot thank you

[@3minutemaths]

Glad the video helped Srinivasa Yasa :-)

[@LiFeInTeRoRzz]

Thanks so much.

[@3minutemaths]

That's great - thanks for letting me know :-)

[@ShahBO55]

you doing excellent.

[@nerdydivergent8696]

Awesome video it really helped 😀😃👍

[@pen15suckshahaha]

is the formula different if you have the numberator instead of the denominator?

[@3minutemaths]

+Austin Gearing - Hi, it really depends upon how the formula is set up. In all cases you're using SohCahToa so you'll sometimes know either the numerator or the denominator. It's then a case of 'manipulating' the formula to get the answer you want. Here's a playlist with a couple of examples: kzbin.info/aero/PLPglScc3TJ-OSOJnPIs3DyVSTrgMbqD-O Hope it helps and all best S :-)

[@qsconty]

Thank you, helped me!

[@3minutemaths]

That's great Diztriction Tableflippa ! All best S

[@josephallen9772]

Thanks, really helpful!

[@3minutemaths]

+The Organised Mess - Glad to help and all best with your test :-)

[@OriginalWIin]

awesome video! Thank you so much

[@3minutemaths]

Sammy Baker Glad to help :-)

[@chimaamobi9558]

epic stuff you have helped me out alot ;-), but when i checked my calculator i got 0.64 is that correct?

[@3minutemaths]

Hi Chima Amobi that's fine and glad the video helped :-)

[@mrshiz1900]

Great video!

[@3minutemaths]

Thanks Storm Low ! All best S :-)

[@timaden3916]

Thk You SimonDeacon

[@3minutemaths]

Glad to help :-)

[@tatyanabredadafonseca151]

Hi! sorry but isn't the answer 7.4? I keep putting it in my calculator and thats the answer I keep receiving

[@theappleguy97]

Cheers mate really helped :)

[@younismohammad7313]

yo my teacher has been trying to teach me this for like 2 months and i watched ur vid once and i got it lmao my teacher is stupid

[@yaqub5322]

i find this weird but when i input this in the calculator i get an answer less than 1? The input was cos34 x 12= 0.918???

[@3minutemaths]

Yaqub HDGamer Hi .. it might be because your calculator is set to RAD (radians), it needs to be set to DEG (degrees) in the setup menu. Best S

[@DavidJohnson-jw9vn]

sir is it possible that only the opposite side is given with an angle of 90 deg.?

[@3minutemaths]

Hi Kyire Irving ... I'm not really sure what you're asking.... although SohCahToa only works with right angle triangles. I'll post some videos on sin and cosine rules and let you know when done. All best S :-)

[@HerbsUniverse]

thankyou so much

[@howblackgirl9633]

What do you do when its cos instead of sin beacuse my promblems is asking me to find the missing angle by using cos :(

[@edgelord9966]

Press 2nd and Cos and type in your sides in parentheses and divide them (hopefully that made sense)

[@zyaninc]

what if the hyp is 100 ??

[@marshallpulham]

Sin being Opp Over Hyp wouldnt you divide the sin40 by the hypoteneuse not times 10 man its been a while since ive done this

[@3minutemaths]

marshallpulham Hi - you would multiply by the 10. Here's a playlist on dealing with linear equations that might help. All best S :-) kzbin.info/aero/PLPglScc3TJ-Mvi9Gk651-7y-bUJKC2y4H

[@mikemotley1838]

What do you do if the number you are dealing with is above the letter you are finding on the equation? Is it multiply of divide?

[@3minutemaths]

Hi Pat Motley is it possible you can give me an example? Best S :-)

[@mikemotley1838]

Tan37 = 6cm/p

[@3minutemaths]

Hi Pat Motley OK, you need to use a bit of algebra: Multiply both sides by p: p x tan37 = 6 Then divide both sides by tan37 p = 6 / tan 37 Here's a playlist that deals with linear equations.. there aren't any SohCahToa examples but the general ideas might help. kzbin.info/aero/PLPglScc3TJ-Mvi9Gk651-7y-bUJKC2y4H All best S :-)

[@mikemotley1838]

Ok, it's a little clearer now. Thanks mate!! :)

[@Arjun45545445]

thanks for the help but another question i am confused with. it is that i have 2 lengths of 14 cm and 5cm and i have to find the length of the other side of the right triangle

[@3minutemaths]

Hi Arjun - with right angle triangles you generally need to know SohCahToa and Pythagorus. From your question, if it's a right angle triangle and you know two sides you can work out the other side using kzbin.info/www/bejne/Z56bqYWFlrKNp7s. Hope this helps and good luck :-)

[@Arjun45545445]

Simon Deacon thanks for the help

[@modelo1983]

thanks for the video

[@3minutemaths]

***** Glad to help :-)

[@issamhashem7727]

thank you so much sir .

[@3minutemaths]

Glad to help and all best S :-)

[@peruanitatauro]

such great help ! :)

[@Z3NTR0music]

what if i get a question where it doesn't state any angles but tells me for example, the hypotenuse and the adjacent. because these sorts of questions are going to be on my exam

[@3minutemaths]

Hi Z3NTR0 if it's not a right angle triangle, the most common questions are using the cosine rule. Here's a playlist kzbin.info/aero/PLPglScc3TJ-MUKnX9MtRfLX4QSRXcb7v_. I hope it helps. All best S :-)

[@Z3NTR0music]

Simon Deacon thanks for that

[@ismaeldjibrilla3173]

thank you so much :)

[@alansumpton8216]

Really helpful, thanks a lot :)

[@3minutemaths]

Glad to help Alan Sumpton :-)

[@pam2125]

Lil different problem..If your treadmill is 6 ft long and is set at an 8% grade. How high (in feet) is the front end of the treadmill? Thanks

[@3minutemaths]

Hi pam2125 The easiest would be to use sin = opp/hyp so: sin 8 degrees = opp / 6ft 6ft x sin 8 degrees = 0.835 ft (opp) This is around 10 inches. I hope this is OK and all best S :-)

[@pam2125]

Thanks man, all the best

[@JJ-js3sw]

How do you know if you need to use sah cah Toa or if you can just cross multiply? Because when I cross multiply I get .48. But I use sin I get .83. I have 5 answer choices with non of the of them being .83. So if .83 is correct then my answer would be non of the above out of my 5 answer options right?

[@3minutemaths]

Jay Jay Costanzo Hi - here's a playlist with some different examples - might help? If you can give me a specific question I'll be happy to work through. All best with your studies :-) kzbin.info/aero/PLPglScc3TJ-O70PYMn0yiLjm2BgiPV6uN

[@exetercityextremist1056]

thanks again

[@stephenbarker100]

whats the best way get a* or a in gcse maths

[@3minutemaths]

stephen barker I'm just waiting for proof reading on my new book 'How to get an A in maths - 15 top tips.." When it's done I'll send you the link.

[@stephenbarker100]

thats awesome ive got get b for move on to a level and further

[@lawrenceah-weng9513]

I used this to try and find the hyp in a gcse calculator paper but I got 12.85575219 which wasn't bigger than the opp so is it wrong?!

[@3minutemaths]

Hi Lawrence Ah-Weng it might be your calculator is set to radians, rather than degrees?

[@xXxHOLYlightxXx]

oh my god the complication but i'm gonna try my best. thank you :)

[@Jacobss14]

Thank you

[@3minutemaths]

No worries ***** :-)

[@francoisvanheerden1694]

Thx

[@billybobdog5]

why did you use sin 40? why not sin 50? that's the only thing confusing me

[@snakeplay]

You seem like a very nice man ! Also great video mate. Come on you irons?

[@3minutemaths]

Lol Mikey .. bit further North.. Leeds :-)

[@aaronho4189]

very helpful

[@3minutemaths]

Glad to help aaron ho :-)