Not enough information - you don't say how long the angled line is to be.
Suppose your baseline goes from {X0,Y0} to {X1,Y1}.
Your Angle point is {X2,Y2}
Your angle is A (in radians)
The cosine C = cos(A), the sine S = sin(A).
You have to pick a length L.
Then your end point {X3,Y3} would be {X2 + L * C, Y2 + L * S}.
So the 2nd line would be from {X2,Y2} to {X3,Y3}