What are \(\cos (\angle A), \cos (\angle B), \cos (\angle C)\)in radians (or fractions)?
+36916 It is NOT a right triangle, so you cannot us S O H C A T O A
You will need to use the cosine law
c^2 = a^2 + b^2 - 2 a b cos c
8^2 = 5^2 + 7^2 - 2 ( 5 ) (7) cos A solve for cos A similar for the others
