hi Agnishom,

I've done a few of these over the last two years.  The method uses vector geometry and the cosine rule.  See

http://www.mathisfunforum.com/viewtopic.php?id=16061

Post 30.

I think Wiki also gives the co-ordinates of the points in 3D so you can pick two adjacent faces, get the critical lines and apply the method.

I've got a post to make for MIF, so It'll be a while before I can put all the figures to this, so have a go yourself. 

Bob

ps.  I have a vague memory that I have done it in a thread, but I couldn't find it.

hi rajinikanth0602

Yes, I expect someone can.  But shouldn't you respond to

http://www.mathisfunforum.com/viewtopic.php?id=18761

first?

Bob