EXAMPLE
Find the distance between the points A(−4, −3) and B(5, 7).
SOLUTION
In this case, x1 = −4, x2 = 5, y1 = −3 and y2 = 7.
AB2 = (x2 − x1)2 + (y2 − y1)2
= (5 − (−4))2 + (7 − (−3))2
= 92 + 102
= 181
Thus, AB =
Note that we could have chosen x1 = 5, x2 = −4, y1 = 7 and y2 = −3 and still obtained the same result. As long as (x1, y1) refers to one point and (x2, y2) the other point, it does not matter which one is which.
