if m∠CBA = 180, then m∠XAB = m∠XAC

Start from the conclusion and work back up the proof. Click the arrow to show the parents.

• m∠XAB = m∠XAC,

  if a = b, then b = a

  • m∠XAC = m∠XAB, if m∠CBA = 180, then m∠XAC = m∠XAB
    • m∠CBA = 180