Drag point D to move E around the ellipse. 
The perimeter of triangle ABE is shown in 
spreadsheet. 

A = Point(xAxis)
B = Point(xAxis)
c = Circle(A, B)
d = Circle(B, A)
C = Intersect(c, d, 1)
e = Ellipse(A, B, C)
distanceAC = Distance(A, C)
distanceBC = Distance(B, C)
circumferencee = Circumference(e)
D = (9.04, 3.26)
a = Ray(A, D)
E = Intersect(e, a, 1)
b = Segment(B, E)
f = Segment(A, E)
AE = Distance(A, E)
BE = Distance(B, E)
A2: BE
AB = Distance(A, B)
A3: AB
A1: AE
A4: A1 + A2 + A3