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another random maths question

Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
in General Chat
Does anyone know how to work out the length of one side of a triangle when two are known, and when the angle is known?

eg in this diagram

ETA: I am fully aware that i am thick, i have googled it with no joy

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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    something to do with pythagoras?? i'm not sure....
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    SOH-CAH-TOA

    god i cant believe i can remember stuff from GCSE maths
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    is it the A^2 + B^2 = H^2 thingy...

    Or it might be the SIN COS TAN thing with SOH CAH TOA...
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    minimi38 wrote:
    SOH-CAH-TOA

    pardon?
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    minimi38 wrote:
    SOH-CAH-TOA

    god i cant believe i can remember stuff from GCSE maths

    yeah i think it'll be SOH-CAH-TOA thats the 1!!!
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    http://www.mathwords.com/s/sohcahtoa.htm

    Read all about it..
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Sine Opposite/hypotenuse Cosine Adjacent/hypotenuse Tan opposite/adjaent.

    I think. Its probably different look up trigonometry in your text book.
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    You want the opposite (of the angle) so you use which one finds you the opposite from the ones that are given, in your case adjacent and hypotenuse.
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Label the triangle with the appropriate names (Hypotenuse, Opposite, Adjacent)

    Then use SOH CAH TOA. Sin = Opposite/Adjacent

    Cos = Adjacent/Hypotenuse

    Tan = Opposite/Adjacent

    Then work it out from there.
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    Dr PirateDr Pirate Posts: 8,303 Legendary Poster
    A Squared + B Squared = C Squared
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Dr Pirate wrote:
    A Squared + B Squared = C Squared
    That's for right angle triangles :p.
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    ooh GCSE maths is all coming back to me now, thanks everyone!
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    hmm it appears that the SOH CAH TOA thingymebob is only for triangles that have a right angle...mine doesnt


    :confused:
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Isn't pythagoras only for right angles triangles?
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    http://www.sparknotes.com/testprep/books/sat2/math2c/chapter9section9.rhtml
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Two fundemental rules:

    Sine rule
    sinA/a = SinB/b = SinC/c

    Cosine rule
    c^2 = a^2 + b^2 - 2abCosC

    where a lower case letter is the side and the upper case letter is the angle.

    On your example, use cosine (C being the unknown):

    c^2 = 100+100 - 2*(100)*Cos11.25
    c^2 = 200 - 200Cos11.25
    c^2 = 200 - 196.2
    c^2 = 3.8
    c = 1.95ft (round it off to 2ft if you want)

    I think that's right...
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    i hate trigonometry
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Sine rule
    sinA/a = SinB/b = SinC/c

    Cosine rule
    c^2 = a^2 + b^2 - 2abCosC

    where a lower case letter is the side and the upper case letter is the angle


    These are the rules you want, havent checked but remember doing it for my As/A level maths
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    mystifymysoul wrote:
    Or it might be the SIN COS TAN thing with SOH CAH TOA...

    Good old SOH CAH TOA, havent heard that since i finished GCSE maths :lol:
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    freeallangels19 wrote:
    Sine rule
    sinA/a = SinB/b = SinC/c

    Cosine rule
    c^2 = a^2 + b^2 - 2abCosC

    where a lower case letter is the side and the upper case letter is the angle


    These are the rules you want, havent checked but remember doing it for my As/A level maths

    Did you just copy my post? :p
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Blatantly. For future reference because SOHCAHTOA is rubbish to remember

    Sex On Hard Concrete Always Hurts The Old Arse.
    Sin, opposite over hypoteneuse. Cos, adjacent over hyp. Tan Opp. Over Adj.
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Yer.
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    Dr PirateDr Pirate Posts: 8,303 Legendary Poster
    Capacity wrote:
    Yer.
    Another quality post there Capacity
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Dr Pirate wrote:
    Another quality post there Capacity

    No doubt you would have said the same if I'd left it unedited. I encourage everyone to speak before engaging their brain. Then, and only then, can we all be more like me.
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    Dr PirateDr Pirate Posts: 8,303 Legendary Poster
    Capacity wrote:
    No doubt you would have said the same if I'd left it unedited. I encourage everyone to speak before engaging their brain. Then, and only then, can we all be more like me.
    Capacity wrote:
    yer.
    :yeees:
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Dr Pirate wrote:
    :yeees:

    ?

    It's an arguement I can't even be arsed to get into.

    I wrote something, decided I wanted to change it; needed to change it quick before some moron tried to pick me up on my point, and changed it to 'yer' (I even openly admitted that I didn't think before writing, how hard do you think that was?). When you stop flooding threads with retired shit like 'hiu2 olol', then and only then can you criticize what I say.
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    Dr PirateDr Pirate Posts: 8,303 Legendary Poster
    #24 Today, 10:55 AM
    Capacity
    Uber Join Date: Feb 2003
    Location: Paws
    Posts: 3,737

    Yer.
    __________________

    [My LiveJournal Tbqmfh.] - Last Updated: 5th April 05

    "Capacity, why do you have to be so horrible to everyone?" - *TiNk*

    Saw nothing about an edit there, so stop getting your feathers up.
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    he edited it. I saw what he originally posted.
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    If nobody manages to view it in time, It doesn't give the message. ;'(
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    Dr PirateDr Pirate Posts: 8,303 Legendary Poster
    Capacity wrote:
    If nobody manages to view it in time, It doesn't give the message. ;'(
    Quite lame tbh ;<
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