In a quadrilateralABCD, ∠A=150∘, ∠B=∠C=∠D.Find angle B,C,D.
Given: ∠A=150∘
We know that sum of all angles of quadrilateral is equal to 360∘
Therefore,∠A+∠B+∠C+∠D=360∘
⇒150∘+∠B+∠C+∠D=360∘
⇒150+3∠B=360∘ [As ∠B=∠C=∠D]
⇒3∠B=360∘−150∘
⇒∠B=2103
∴∠B=∠C=∠D=70∘