Question

In figure, if AB || CD and CD || EF, find ∠ACE.

Answer 1

Given: CD || EF 

∠FEC + ∠ECD = 180° [Sum of co-interior angles is supplementary to each other] 

∠ECD = 180° – 130° = 50° 

Also, BA || CD 

∠BAC = ∠ACD = 70° [Alternative angles of parallel lines are equal] 

But, ∠ACE + ∠ECD = 70°

∠ACE = 70° - 50° = 20°