In Euclidean geometry, the Euclidean distance is the usual distance between two points p and q. This distance is measured as a line segment. The Pythagorean theorem can be used to calculate this distance.
Euclidean distance on the planeEdit
Alternatively, if the polar coordinates of the point p are (r1, θ1) and those of q are (r2, θ2), then the distance between the points is