In the given figure, ABCD is a parallelogram in which ∠BDC=45∘ and ∠BAD=75∘. Then, ∠CBD= ?
(a) 45∘
(b) 55∘
(c) 60∘
(d) 75∘
ANSWER:
(c) 60°
Explanation:
∠BAD = ∠BCD = 75∘
[Opposite angles are equal]
In ∆ BCD, ∠ C = 75∘
∴ ∠ CBD = 180∘ − (75∘ + 45∘ ) = 60∘