Jawabanmu

2014-09-03T17:21:17+07:00
 R^{2} ={a ^{2}+ b^{2} + 2.a.b.cos \alpha
 14^{2} { 8^{2}+ 10^{2}+2.8.10.cos \alpha
196 = 64 + 100 +160 cos  \alpha
196 - 164 = 160  cos  \alpha
32 = 160 cos  \alpha
cos  \alpha  \frac{32}{160}
cos  \alpha = 0,2
 \alpha =  cos^{-1} 0,2
1 5 1
2014-09-03T18:43:40+07:00