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Edexcel C2 sine and cosine rule help

I don't understand how to work out Exercise 2F question 6c). Any help on how to find x? See attachment for question. Thanks :smile:

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It's quite difficult. Can you find any of the other lengths or angles? This will allow you to work towards the one you want.
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Original post by otakulei
I don't understand how to work out Exercise 2F question 6c). Any help on how to find x? See attachment for question. Thanks :smile:

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The angle ACB is 130.
Let BC be y then with cosine rule
112=3.82+y27.6ycos130o11^2=3.8^2+y^2-7.6\cdot y\cdot \cos 130^o
from this you will get y

Let the BAC angle is α\alpha
WIth cosine rule
y2=3.82+1127.611cosαy^2=3.8^2+11^2-7.6\cdot 11\cdot \cos \alpha
from this you will get α\alpha

Then a sine rule for triangle ADC will give the angle x
the angle ADC is 180oαx180^o-\alpha - x

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