Tangents & Chords

Right angles and products

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

• A tangent is perpendicular to the radius at the point of contact.
• The two tangents from an external point are equal in length.
• Crossing chords: $AE \times EB = CE \times ED$.

Steps

1. Tangents
2. Tangent length
3. Crossing chords
4. Belt around two tangents
5. Tangent of length 4
6. Intersecting chords