+130477 Cos c= 0.6879 , who do you get c by self. whats C= ?
We're just trying to find an angle whose cosine = .6879
You can use the on-site calculatoer for this.......just hit the "2nd" button, the "acos" button, and type in the value you're looking for. "Acos" stands for "cosine inverse" - sometimes written as cos-1(x).
So, acos(.6879) ≈ 46.54°
Be careful......since the cosine also has a positive value in the 4th quadrant, this might be a 46.54° angle in that quadrant......i.e., 313.46° 
