Trig
posted by Lisa .
Can you show us how to use law of cosines to show that theta equals inverse cosine of (a^2 + b^2 484)/(2ab) where a^2=(7+xcos a)^2 + (28xsin a)^2 and b^2=(7+xcos a)^2 + (xsin a 6)^2? Thanks

Lisa, saw that one last night,
confused about the angle 'a'
in xcosa and xsina.
secondly where does x come in ?
describe your triangle.
I have a triangle with sides a and b and Ø as its contained angle.