- smaller diagonal

- larger diagonal

, - sides of a parallelogram

- acute angle between diagonals

- obtuse angle between diagonals

- area of a parallelogram

Formulas for calculating angles between diagonals if given sides and diagonals :

Formula for calculating angle between diagonals if given area of a parallelogram and diagonals :

Formulas for the relation of the acute and obtuse angles between diagonals: :