Angles on parallel lines visualiser tool

Use this interactive parallel lines angle visualiser to explore corresponding (F), alternate (Z) and co-interior angles (C). Move the transversal, highlight different angle pairs, and hide or reveal angle values to test your understanding.

This tool is designed for maths students learning angle facts on parallel lines. It can also help teachers demonstrate F-shape, Z-shape and C-shape angle relationships without relying on a static diagram. But always use the correct terminology!

Key angle facts

• Corresponding angles (F) are equal. They are in the same position at each crossing.
• Alternate angles (Z) are equal. They are inside the parallel lines on opposite sides of the transversal.
• Co-interior angles (C) add to 180° (supplementary). They are inside the parallel lines on the same side of the transversal.
• Vertically opposite angles are equal.
• Angles on a straight line add to 180°.