Can you use the Law of Cosines in the triangle below? Why or why not?
triangle whose sides measure 15, 21, and 22 units long

Question

Can you use the Law of Cosines in the triangle below? Why or why not?
triangle whose sides measure 15, 21, and 22 units long

anonymous · Answer

attachment

mathmale · Answer

What are YOUR thoughts about this?  
Does this appear to be a right triangle, or not (not that it matters here)?

anonymous · Answer

it doesn't look like a right triangle

mathmale · Answer

If this is not a right triangle, then the Pythagorean Theorem doesn't apply.  However, I see no reason why we couldn't apply the Law of Cosines.

$$a ^{2}=b ^{2}+c ^{2}-2bc*\cos A$$ where side a is opposite Angle A.  What else do you need to know to complete your answer to this question?