MAT517-ClassActivity
Author: test
Date: 21 April 2014

Compute the area of the quadrilateral $\square CDFE$, 
 if area of $\triangle ABF$ is 20,  

area of $\triangle DFB$ is 15, 
and area of $\triangle EFA$ is 8.

A = (0.04, 4.82)
B = (3.74, -0.32)
C = (-3.8, -0.98)
poly1, c, a, b = Polygon(A, B, C)
D = Point(a)
d = Segment(D, A)
E = Point(b)
e = Segment(B, E)
F = Intersect(d, e)