Please find the graph file in the attached file and proving can be defined as follows:
As the given graph:
[tex]\to \bold{AE || CD}[/tex]
So,
[tex]\to \bold{\angle AEC=\angle DCE }\\\\[/tex]
AS
[tex]\to \bold{AB || CE}[/tex]
So,
[tex]\to \bold{\angle ABC=\angle ECF \ \ \ \ \ \text{parallel property}}\\\\\to \bold{\angle CDE=\angle DCF +\angle CFD \ \ \ \ \ \ \ \ \ \text{property of sum of outer angle of a traingle}} \\\\[/tex]
AS
[tex]\to \bold{\angle ABC =\angle CDE} \\\\[/tex]
So
[tex]\to \bold{\angle ABC=\angle DCF +\angle CFD = \angle ECF}\\\\\to \bold{\angle ECF= \angle DCF +\angle DCF \ \ \ \ \ \ \ \ \ \ \text{angle exchange}}\\\\[/tex]
So,
[tex]\to \bold{\angle DCF +\angle CFD = \angle DCE+ \angle DCF}\\\\\to \bold{\angle DCE =\angle CFD = \angle AEC}\\\\[/tex]
So,
[tex]\to \bold{\angle AEC= \angle CFD}[/tex]
Learn more:
brainly.com/question/24211031
