find the distance betwwen A(4,-5) and B(5,-8)

A(4,-5) and B(5,-8)    the distance between these points is given by :

sqrt [ (5 - 4)^2  + (-8  - (-5) ) ^2]  =

sqrt [  (1)^2 + (-3)^2 ]  =

sqrt  [ 1 + 9]  =

sqrt(10)   = about 3.162 units