Answer:
1:
<B=131°
BC=a=11
AB=c=8
AC=b
By using cosine rule:
b²=a²+c²-2acCosB
b²=11²+8²-2*11*8*Cos 131°
b=[tex]\sqrt{300.5}=17.3[/tex]
AC=17
2;
<C=?
BC=a=7
AB=c=10
AC=b=6
By using cosine rule:
c²=a²+b²-2abcos C
10²=7²+6²-2*7*6Cos C
84Cos C=7²+6²-10²
Cos C=-15/84
C=Cos-¹(-15/84)
<C=100°
