# Thread: Find the unknown side of a triangle?

1. ## [Solved]Find the smallest angle in a triangle?

I'm lost in this question.

Find the smallest angle of triangle ABC in which a:b:c = √2 : √3+1 :2

2. ## Re: Find the smallest angle in a triangle?

The smallest angle will be opposite the smallest side, which side do you think is the longest?

After you know this apply the cosine rule to find the angle.

3. ## Re: Find the unknown side of a triangle?

angle A is the smallest

4. ## Re: Find the unknown side of a triangle?

Yes angle A is the smallest, therefore,

$A = \cos^{-1}\left(\frac{b^2+c^2-a^2}{2bc}\right)$

5. ## Re: Find the unknown side of a triangle?

Oh I see.....so that's actually nothing complicated to this question! I've always overlooked things.
And I believe the answer is 30 degrees.

Thank you so much!