Question

In a $\Delta ABC$, if $b=16,c=20$ and $\sin A=\frac{3}{5}$, then $a=$

• A. $12$
• B. $13$
• C. $14$
• D. None of these

Answer 1

The correct option is A $12$

In $△ABC,b=16,c=20$

$\sin A=\frac{3}{5}⟹\cos A=\frac{4}{5}$

AS we know that

$a^2=b^2+c^2-2ab\cos A={16}^2+{20}^2-2\left(16\right)\left(20\right)\times \frac{4}{5}=256+400-512=144$

$⟹a=12$