Paper 1 · Module
Coordinate geometry
Gradient, length, midpoint and equations of lines
The three measurements of a line segment (gradient, length and midpoint), the three forms of the equation of a straight line, and how to find where lines cross.
≈ 35 minParallel and perpendicular lines
Why parallel lines share a gradient and perpendicular gradients multiply to , and how to use that for perpendicular bisectors, the foot of a perpendicular and right-angled shapes.
≈ 35 minThe equation of a circle
Why is a circle, how to find the centre and radius from the expanded form by completing the square, and how to use diameters and right angles to find a circle's equation.
≈ 40 minTangents, chords and intersections
The two right angles that unlock circle questions (tangent and radius, centre and chord), and how substituting a line into a circle or curve turns geometry into a quadratic whose discriminant tells you how they meet.
≈ 45 min