Question

In a $△ABC$, if $a=26,b=30,\cos C=\frac{63}{65}$ then $c=$

• A. $2$
• B. $4$
• C. $6$
• D. $8$

Answer 1

The correct option is D $8$

Given

In $△ABC,a=26,b=30,\cos C=\frac{63}{65}$

As we know that

$c^2=a^2+b^2-2ab\cos C={26}^2+{30}^2-2\left(26\right)\left(30\right)(\frac{63}{65})=64$

So $c=8$