I need help proving BF is congruent to ED.
Angle FBC is congruent to Angle EDA
The parallel sides of the parallelogram are congruent
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CPCTC means 'corresponding parts of congruent triangles are congruent' and..
Angle FBC is congruent to angle EDA - given.
BC=AD - The parallel sides of the parallelogram are congruent
Angle BCA is congruent to angle CAD - WHY?
From the above we can conclude that:
triangle FBC congruent to triangle EDA. (ASA)
So, BF=ED (corresponding sides on congruent to triangles).