if WX || YZ and m∠WSX = 180 and m∠YTZ = 180, then m∠XST = m∠STY

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

• m∠XST = m∠STY, if (WX || YZ) and (m∠WSX = 180) and (m∠YTZ = 180), then m∠WST = m∠STZ
  • XW || ZY, if AB || CD, then BA || DC
    • WX || YZ
  • m∠XSW = 180, if m∠ABC = x, then m∠CBA = x
    • m∠WSX = 180
  • m∠ZTY = 180, if m∠ABC = x, then m∠CBA = x
    • m∠YTZ = 180