1. Properties of a bisector of a parallelogram
By definition, the bisector divides the angle in halves :
The bisector cuts out an isosceles triangle (in this case, the triangles ABF and DKC) :
The bisectors of the supplementary angles intersect at a right angle :
The bisectors of the opposite angles are equal and parallel :
- bisector of an acute angle
- bisector of an obtuse angle
, 
- sides of a parallelogram
- acute angle
- obtuse angle
Since ABF and DKC are isosceles triangles, the following identities hold :
2. The length of a bisector of a parallelogram
, - sides of a parallelogram
- acute angle
- obtuse angle
- bisector
Find length of bisector of a parallelogram if given side and angle ( L ) :
