Distance Between 2 Points
Here is how to calculate the distance between two points when you know their coordinates:
 |
Let us call the two points A and B |
| |
|
 |
We can run lines down from A, and along from B, to make a Right Angled Triangle.
And with a little help from Pythagoras we know that:
a2 + b2 = c2 |
| |
|
 |
Let us now label the coordinates of points A and B.
xA means the x-coordinate of point A
yA means the y-coordinate of point A
The horizontal distance "a" is (xA - xB)
The vertical distance "b" is (yA - yB) |
So now we can solve for c (the distance between the points):
| Start with: |
|
c2 = a2 + b2 |
| |
|
|
| Put in the calculations for a and b: |
|
c2 = (xA - xB)2 + (yA - yB)2 |
| |
|
|
| And the final result: |
|
 |
Examples
Example 1
Example 2
It doesn't matter what order the points are in, because squaring removes any negatives:
Example 3
And here is another example with some negative coordinates ... it all still works:
|
Home
