Question:
In the given figure, BAD || EF, ∠AEF = 55° and ∠ACB = 25°, find ∠ABC.
Solution:
In the given figure, EF || BD and CE is the transversal.
∴ ∠CAD = ∠AEF (Pair of corresponding angles)
⇒ ∠CAD = 55°
In ∆ABC,
∠CAD = ∠ABC + ∠ACB (Exterior angle of a triangle is equal to the sum of the two interior opposite angles)
⇒ 55° = ∠ABC + 25°
⇒ ∠ABC = 55° − 25° = 30°
Thus, the measure of ∠ABC is 30°.