Final answer:
The declarative solution is to use a database query to retrieve and display the highest opportunity amount on the related account using SQL.
Step-by-step explanation:
The declarative solution for displaying the highest opportunity amount on the related account is to use a database query to retrieve the maximum opportunity amount and then display it on the account page. This can be achieved using SQL, a programming language for managing and manipulating relational databases.
For example, if you have a table called 'opportunities' with columns for 'amount' and 'account_id', you can write a query like:
SELECT MAX(amount) FROM opportunities WHERE account_id = 'related_account_id'
This query will return the highest opportunity amount for the specified related account.