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# Trig Problem (C2) watch

1. In triangle ABC, AB = x xm, BC = (4-x) cm, angle BAC = y degrees and angle BCA = 30 degrees.

Given that sin y degrees = 1/sqrt(2), show that x = 4(sqrt(2)-1).

So far ive drawn the triangle and worked out y to be 45 degrees and put

x/sin30 = (4-x)/sin35

So x = (4-x)sin30 / sin35

Now what?

Thanks
2. bump
3. (Original post by matt_copas)
In triangle ABC, AB = x xm, BC = (4-x) cm, angle BAC = y degrees and angle BCA = 30 degrees.

Given that sin y degrees = 1/sqrt(2), show that x = 4(sqrt(2)-1).

So far ive drawn the triangle and worked out y to be 45 degrees and put

x/sin30 = (4-x)/sin35

So x = (4-x)sin30 / sin35

Now what?

Thanks
Why has 45 deg suddenly switched to 35 deg?

Sin30 / sin 45 = root(2) / 2

Sub that in and continue from there.

Remember 2 / root(2) = root(2) and also remember what you need to do to simplify when you get something like this:

Something / (Number + or - a root)

eg. 5 / (1 + root(7) ) .

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