Given:
The sides of the triangle ABC are given
a=7, c= 8 and b= 13.
To find
The angle C.
Explanation:
To find angle C , use the cosine rule.
[tex]c^2=a^2+b^2-2ab\cos C[/tex]Substitute the values in the cosine rule.
[tex]8^2=7^2+13^2-2\times7\times13\cos C[/tex][tex]64=49+169-182cosC[/tex][tex]182\cos C=49+169-64[/tex][tex]182\cos C=154[/tex][tex]\cos C=\frac{154}{182}[/tex][tex]C=\cos ^{-1}(0.846)=32.2^{\circ}[/tex]Answer :
Hence the angle C is obtained as 32.2 degree.