MathDB

In a convex quadrilateral

ABCD

E

is the intersection of

AB

and

CD

F

is the intersection of

AD

and

BC

and

G

is the intersection of

AC

and

EF

. Prove that the following two claims are equivalent:

(i)

BD

and

EF

are parallel.

(ii)

G

is the midpoint of

EF

Problem Statement