C^2 = A^2 + B^2 -2AB cosC

The Laws of Sines and Cosines. The Law of Sines establishes a relationship between the angles and the side lengths of ?ABC: a/sin(A) = b/sin(B) = c/sin(C).

and you’d have to guess again. This guess-and-check method is looooooong and tedious, at best. In fact, this particular quadratic is prime, so you could guess and check all day long and it would never factor. If you’re in pre-calculus and your teacher …

Angles Outside a Circle An angle is outside a circle if its vertex is outside the circle and its sides are tangents or secants. The possibilities are: an angle formed by two tangents, an angle formed by a tangent and a secant, and an angle formed …