Two reagents that can be used to remove tea stains from a white cotton tablecloth are:
1. Vinegar – Vinegar helps to break down the stain.
2. Baking soda – Baking soda is mildly abrasive and can help lift the stain from the fabric.
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.