Co-ordinate Geometry

Co-ordinate geometry (AS91256) puts algebra and geometry on the same grid: points become pairs of numbers, and lines become equations. With four core tools — distance, midpoint, gradient, and the equation of a line — you can measure lengths, find centres, test whether lines are parallel or perpendicular, and locate where they cross. This internal is assessed in a real context (a map, a plan, a design), so the marks come from choosing the right tool and linking several of them together.