Question

In $\Delta ABC$; with usual notations, if $\cos A=\frac{\sin B}{\sin C}$, then the triangle is _______.

• A. Acute angled triangle
• B. Equilateral triangle
• C. Obtuse angled triangle
• D. Right angled triangle

Answer 1

The correct option is D Right angled triangle

We know that $2RSinB=b=AC$ and $2RSinC=c=AB$

Thus, $cosA=\frac{AC}{AB}$ .

Using above relation we can claim that $△ABC$ is a right angled triangle with AB as hypotenuse ,right angled at C.