Please help in this difficult math geometry quiz.

 From:  Elang
11167.19 
Hello all... Thank you very much for thoroughly replies.

I'm very sorry that I'm out of town for about a week (it's been 2 days till now), and I don't have access to Moi for this time being. So I'll keep reading your replies and will be continue to solve the task based on all of your replies immediately.

Cheers!