20. Exemplar example problems I

1. If angle between two radii of a circle is $130^\circ$, the angle between the tangents at the ends of the radii is:

 

2. In figure, the pair of tangents $AP$ and $AQ$ drawn from an external point $A$ to a circle with centre $O$ are perpendicular to each other and length of each tangent is $5 \ cm$. Then, the radius of the circle is: