Perpendiculars & Parallels

Right angles and parallel lines

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Perpendicular from P: circle round P, then bisect the chord it cuts.
• Parallels: copy an angle (equal corresponding angles).
• Changing the parallel postulate gives spherical and hyperbolic geometry.

Steps

1. Dropping a perpendicular
2. Find the foot
3. A parallel line
4. Shortest distance
5. Distance to a line
6. Euclid’s fifth