display 3 digits before decimal and after decimal point 6dig

Question

How to Display three digits before decimal and after decimal point six digits in SQL Server

 I had column called longitude and latitude with data type like "nvarchar". when user can enter something like (23.23424432) ,(432423.343) this for should not take only this format should accept.(232.343244) please can can any help me how to validate this in Sql server.

 

Data that can be Entered by user:- Ex: 0, 12, 101.0, 111.022222

Data that can’t be Entered by user : - Ex: 1111, 111.2222222, 1234.1111

 

It should accept only  this format: (232.343244)