1. Writing a point as (x, y)
A point in two dimensions is fixed by two Cartesian coordinates, written in brackets as (x, y). The x-coordinate comes first. It says how far the point is along the horizontal x-axis.
The y-coordinate comes second. It says how far the point is up the vertical y-axis.
Examiner insight
Worked example 12 marks
The diagram shows triangle PQR drawn on a grid.
(a) Write down the coordinates of R.
(b) Write down the letter of the point with the same x-coordinate as Q.
- 1
R is 6 across and 4 up, so R = (6, 4) [1]
- 2
Q is at (6, 1). R also has x-coordinate 6, so the point is R [1]