dynamic block intersection when changing angle

[mvrp350]

Hello,

 

I'm having a hard time finding the solution for my problem.

 

I want to create a dynamic block in Autocad 2014 In this block I need to determine the intersection between 2 lines.

 

In the sample you'll see my problem.

I want to make A, B and C variables in my block. The angle on top is always 90 degrees.

With this information I can draw everything, but I don't know how to make the intersection properly, and keep it clean when manipulating the variables.

Variable A has to be positive between 1 and 89 degrees, there are no restrictions on the variables C.

 

Any help is much appreciated

 

mvrp350

intersection problem.dwg