Alternate interior angles sit on opposite sides of the transversal and between the parallels — if the lines are parallel they are equal.

Angle 3 and angle 5: 122° = 122°
Angle 2 and angle 8: 58° = 58°

Transversal angle — 58°Distance between the parallels

Show all eight angles

More themes unlock on the teacher plan and above.

⚠️ At ป.5 the term “มุมแย้ง” means the INTERNAL alternate pair only — an agreement the IPST teacher's manual has the teacher announce to the class — and the chapter contains no vertical angles. This tool shows neither, on purpose.