In $\Delta PQR$, $PQ=5$ cm, $PR=6.5$ cm and $QR=\sqrt{x}$ cm. Given that \(\cos \angle

Question

In $\Delta PQR$, $PQ=5$ cm, $PR=6.5$ cm and $QR=\sqrt{x}$ cm. Given that $\cos \angle QPR = -\frac{11}{52}$, find the value of $x$.

Accepted Answer

$81$

Trigonometric Analysis of Non-Right Angled Triangles