You need to know the following important formulae and rules:
- Distance between two points is found by Pythagoras' theorem:
- Coordinates of the midpoint of a line are the midpoints between the two coordinates:
- Gradient of a line is change in y ÷ change in x (or )
- If two lines are perpendicular,
- The most commonly used equation of a straight line is
- You can also use if you have two known points.
- Points of intersection (where two lines cross) can be found using simultaneous equations.