Sides BA and DC of quadrilateral ABCD are extended as per diagram, then which one of the following is true ?

In the given figure, ABCD is a square. Angle DEC = 75 degrees. What is the value (in degrees) of angle EFA?

In the given figure, what is value (in degrees) of Q?

Let ABCD be a quadrilateral which satisfies any of the following conditions.
( i ) opposite sides are equal
( ii ) each diagonal of ABCD divides it into congruent triangles
( iii ) each pair of opposite angles are equal
( iv ) diagonals of ABCD bisect each other
Then ABCD has to be a _____________

How many diagonals can be there in a regular polygon with 37 sides?

A parallelogram is a quadrilateral in which:

The number of diagonals in a hexagon is :

ABCD is a trapezium in which BC || AD and AC = CD. If ∠ABC = 54° and ∠BAC = 60°, then what is the measure of ∠ACD (in degree)?

ABCD is a trapezium in which BC || AD and AC = CD. If ∠ABC = 19° and ∠BAC = 137°, then what is the measure of ∠ACD (in degree)?

The diagonals AC and BD of a parallelogram ABCD intersect each other at the point O. If ∠DAC = 32° and ∠AOB = 70°, then ∠DBC is equal to-

ABCD is a cyclic quadrilateral such that AB is a diameter of the circle circumscribing it and $$\angle ADC = 140^\circ.$$ 
Then $$\angle BAC$$ is equal to: