In Level 2 NCEA Coordinate Geometry, finding the equation of a line isn’t usually a random skill on its own. You use it when you need to prove or show something about a line, or when the line itself becomes part of a bigger argument.

Here are the main contexts it comes up in during an assessment:

1. Showing lines are parallel or perpendicular 

2. Finding intersections 

3. Proving collinearity 

4. Geometric proofs using coordinates eg. showing a quadrilateral is a parallelogram, proving a triangle is right angled, showing a line is a perpendicular bisector