1. Passive play refers to activities like playing alone with toys (iii).
2. Active play involves physical activities such as cycling (i).
3. Exploratory play refers to activities like opening up toy car screws (iv).
4. Natural play is playing with dolls or other imaginative play (ii).
In the adjoining figure, $\triangle CAB$ is a right triangle, right angled at A and $AD \perp BC$. Prove that $\triangle ADB \sim \triangle CDA$. Further, if $BC = 10$ cm and $CD = 2$ cm, find the length of AD. 
In the adjoining figure, TP and TQ are tangents drawn to a circle with centre O. If $\angle OPQ = 15^\circ$ and $\angle PTQ = \theta$, then find the value of $\sin 2\theta$. 