What is distance between coordinates?
On a grid, every point has coordinates written as (x, y). When two points sit on the same horizontal line, they share the same y-coordinate. When they sit on the same vertical line, they share the same x-coordinate.
To find how far apart two such points are, we subtract the smaller number from the bigger number in the coordinate that changes. The answer is counted in units, which is the same as the number of grid squares between the points. You can always check your working by counting the squares one by one along the line.
Key idea
Same y (horizontal): distance = difference of x-values. Same x (vertical): distance = difference of y-values.
Worked example
Worked example
Find the distance between A(2, 3) and B(8, 3).
Both points have the same y-value, y = 3, so they lie on a horizontal line.
Only the x-values change, from 2 to 8.
Distance = 8 − 2 = 6 units.
Counting the squares from 2 to 8 also gives 6, so the answer is correct.
Remember
- Only subtract the coordinate that changes.
- Always take bigger − smaller so the answer is positive.
- Write the answer in units.