The procedure for buying goods through mail order includes the following steps:
1. Catalog Selection: The buyer selects products from a catalog or online store.
2. Order Placement: The buyer places an order by filling out a form or placing an online request.
3. Payment: Payment is made in advance or upon delivery through cash, cheque, or online payment methods.
4. Order Processing: The seller processes the order and prepares the goods for dispatch.
5. Delivery: The goods are delivered to the buyer through postal or courier services.
Example: Buying books from an online retailer like Amazon follows a similar mail-order process.
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.