In the context of drills, the term 'Cover' refers to the positioning of one person behind another in a formation, with each person aligned to the side of the person in front of them. This ensures that everyone is positioned uniformly and is ready to respond in a structured manner during drills.
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.