Coordinates are pairs of numbers written as (x,y) which takes up a specific space in the cartesian plane. You can determine the linear distance between any points in the plane by using the derived form of the distance formula. Suppose you want to find the distance between Point 1 (5,2) and Point 2 (3,9). You use the equation:
d = √[(x2-x1)^2 + (y2-y1)^2]
Such that,
d = √[(3-5)^2 + (9-2)^2]
d = 7.28 units
Note that the assigning of which one is point 1 or which one is point 2 is arbitrary. Either of those would yield the same answer as long as you remain consistent with the given pair of coordinates.