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Help solving triangle please

Hey guys and girls I have a maths problem I'm stuck on I keep seeming to get the wrong answer when I move on to work out the angle of the triangle. Attached is the question and my working sheet in an image format. If anyone could tell me where I've gone wrong and help that would be great!

Thanks in advance.Attachment 28412

Attachment 28413Attachment 28413Like I said it is when using the cosine rule to work out the angle that I struggle and seem to get the wrong answer.

Re: Help solving triangle please

Can you upload the picture to imgur or some place? I can barely read the text.

Re: Help solving triangle please

Here's the link to view the images: matt4935's uploaded images - Imgur

Re: Help solving triangle please

Quote:

Originally Posted by

**matt4395**

"matt4935's images are not publicly available."

Re: Help solving triangle please

Hey sorry about that new to using this website.

imgur: the simple image sharer

imgur: the simple image sharer

Hope this works!

Re: Help solving triangle please

You have a triangle, ABD, in which the side AB has length 6m, side BD has length 5m and the angle ABD is 20 degrees. The "cosine law" say that AB has length s where $\displaystyle s^2= 6^2+ 5^2- 2(6)(5)cos(20)= 36+ 25- 10(0.93969)= 61- 9.4= 51.6$

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Re: Help solving triangle please

Re: Help solving triangle please

ah thank you very much I think I see where I have gone wrong now

Re: Help solving triangle please

Poo I meant it was when using the sine rule! Darn! SORRY Guys but yeah I actually did get the Cosine wrong