Coordinate Geometry

Geometry with numbers

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

• Midpoint: average the coordinates. Distance: Pythagoras on the gaps.
• Perpendicular slopes multiply to −1.
• Coordinates turn geometric questions into algebra.

Steps

1. Points as numbers
2. Halfway
3. Distance
4. Perpendicular slopes
5. Equation of a line
6. Area from coordinates