The diagonals of a parallelogram ABCD intersect at O. If ∠BOC=90∘ and ∠BDC=50∘, then ∠OAB(a) 40∘(b) 50∘(c) 10∘(d) 90∘

The diagonals of a parallelogram ABCD intersect at O. If ∠BOC=90∘

1.	The diagonals of a parallelogram ABCD intersect at O. If ∠BOC=90∘ and ∠BDC=50∘, then ∠OAB(a) 40∘(b) 50∘(c) 10∘(d) 90∘
Answer» The diagonals of a parallelogram $A B C D$ intersect at $O .$ If $∠ B O C = 90^{\circ}$ and $∠ B D C = 50^{\circ},$ then $∠ O A B$ (a) $40^{\circ}$ (b) $50^{\circ}$ (c) $10^{\circ}$ (d) $90^{\circ}$