If the diagonal BD of a parallelogram bisects ∠B and ∠D, then ABCD is a
Rhombus
ABCD is a parallelogram (given)
∠B = ∠D = 2x° (say) … (opposite angles of a parallelogram are equal)
Therefore ∠ADB =∠BDC = ∠ABD = ∠DBC = x° ....(DB bisects ∠B and ∠D)
ADB is isosceles …...(base angles are equal to x°)
Therefore, AD = AB ……. (equal sides of an isosceles triangle)
ABCD is a rhombus ….. (all sides of the parallelogram are equal)