Solution:
In Parallelogram B CDE
BC= DE, BC ║DE
CD = BE , CD ║BE
Also, ∠B=∠D and ∠C=∠E →→In a parallelogram opposite sides are equal and parallel, as well as opposite angles are equal.Diagonals Bisect each other.
∠B= 60° , ∠C ED= 40°
CE is a transversal and BC║DE.
∠CED=∠BCE = 40° →→Alternate interior angles
In Δ BCE
∠B + ∠BCE + ∠BEC= 180°→→→Angle sum property of Triangle.
60° + 40° + ∠ B E C= 180°
100° + ∠BEC=180°
∠BEC= 180° -100°
∠BEC= 80°
