CBSE Class 10 Maths (Standard) 2024 · Paper 30/5/1 · Question 21(b)

Each tangent is perpendicular to the radius at its point of contact, so $\angle PAB=90^{\circ }$ and $\angle ABS=90^{\circ }$. These are equal alternate interior angles made by the transversal $AB$, so the tangent $PQ$ at $A$ is parallel to the tangent $RS$ at $B$. Hence proved.