physics repost
posted by Anonymous .
What should be the angle between two vectors of magnitudes 3.20 and 5.70 units, so that their resultant has a magnitude of 6.10 units?
cos=a^2+b^2c^2/2ab
cos10.24+32.4937.21/(2*3.20*5.70)
= 99 degrees

yes, 180  81.3 = 98.7