Question

If below fig, if AB || CD and CD || EF, find ∠ACE.

Answer 1

Since EF || CD

∴ 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°