we know that
There are six important properties of parallelograms to know:
1) Opposite sides are congruent (AB = DC and AD=BC).
2) Opposite angles are congruent (D = B and A=C)
3) Consecutive angles are supplementary (A + D = 180° and D+C= 180°).
4) If one angle is right, then all angles are right.
5) The diagonals of a parallelogram bisect each other.
6) Each diagonal of a parallelogram separates it into two congruent triangles.
Part 1) What is BC?
BC=AD-----------> BC=10 cm--------> by Opposite sides are congruent
the answer Part 1) is
BC=10 cm
Part 2) What is m∠BCD?
m∠BCD=m∠DAB-----> m∠BCD=120°----> by Opposite angles are congruent
the answer part 2) is
m∠BCD=120°
part 3) What is AB?
AB=CD------> AB=5 cm----> by Opposite sides are congruent
the answer Part 3) is
AB=5 cm
Part 4) What is EB?
EB=DE-----> EB=6.1 cm----> by The diagonals of a parallelogram bisect each other.
the answer Part 4) is
EB=6.1 cm