Question:
If below fig. if AB ∥ CD and CD ∥ EF, find ∠ACE..
Solution:
Since EF ∥ CD
Therefore, EFC + ECD = 180 [co-interior angles are supplementary]
⟹ ECD = 180 - 130 = 50
Also BA ∥ CD
⟹ BAC = ACD = 70 [alternative angles]
But, ACE + ECD = 70
⟹ ACE = 70 - 50 = 20