Given:
a=14
b=15
c=17
Find measure of angle B.
Applying law of cosines, we have:
[tex]b^2=a^2+c^2-2ac\cos (B)[/tex]Putting the values,we have:
[tex]15^2=14^2+17^2-2\times14\times17\times\cos (B)[/tex]We have to find B so ,
[tex]\cos \text{ (B)=}\frac{196+289-225}{476}[/tex][tex]\begin{gathered} \cos (B)=\frac{260}{476} \\ =0.5462 \end{gathered}[/tex][tex]B=\cos ^{-1}\text{ 0.5462}[/tex]Hence, the angle B is nearly 60 degrees.
That is,
[tex]m\angle B=60^{\circ}[/tex]This is required answer.
