In the adjoining figure, p∥q. Find the unknown angles.
Given: p∥q
125∘+e=180∘ [Linear pair]
∴e=180∘−125∘=55∘ (i)
e=f=55∘ [Vertically opposite angles]
a=f=55∘ [Alternate interior angles]
a+b=180∘ [Linear pair]
⇒55∘+b=180∘ [From eq. (i)]
⇒b=180∘−55∘=125∘
a=c=55∘ , b=d=125∘ [Vertically opposite angles]
⇒a=55∘, b=125∘c=55∘, d=125∘, e=55∘, f=55∘.