The correct option is
C 30∘ Given:
∠BAD=120∘ and ∠DBC=x ∠B=2∠DBC=2x [Since, diagonals bisect the angles in rhombus]
We have,
∠DAB+∠ABC=180∘ [Co-interior angles on the same side of transversal]
⇒120∘+2x=180∘ ⇒2x=180∘−120∘ ⇒x=602=30∘ Hence, the value of
x is
30∘ .