Question

Quadrilateral below parallelogram

Answer 1

Angles of a parallelogram

Case 1

We have that the diagonals of a parallelogram cut in halfs all the angles. Then, in this case:

because both angles of the sides of the diagonal may be equal.

Then

m∠DEC = 71º

m∠DFE = 21º

Since the opposite angles of the parallelogram are equal too, we have:

And then,

m∠ECD = 71º

Since

71º + 71º = 142º

and

21º + 21º = 42º

then

m∠CDE = 42º

Answers

Then, the answers are:

m∠DEC = 71º

m∠CDE = 42º

m∠ECD = 71º

m∠DFE = 21º

Case 2

If we consider that

m∠FED = 134º

then, we have that