Distance formula

The distance formula enables one to find the distance between two points, given the coordinates of the two points. Let there be two points whose coordinates are A (x1, y1) and B (x2, y2), then the distance formula gives the distance between A and B
AB = 
(x2 - x1)2 + (y2  - y1)2

For example, if there are two points on a coordinate plane A (1, 2) and B (3, 4), distance between them is computed as follows:
AB = 
(3 - 1)2 + (4 - 2)2

Simplifying it, AB = 2√2