To find the distance of two points we need to use the Pythagorean Theorem the distance between points is a hypotenuse of a right triangle.
The Pythagorean Theorem states that:
The Pythagorean Theorem triangles with 90° (right triangles) a and b are the side lengths of the legs while c is the length of the hypotenuse.
In a Cartesian plane the side lengths a and b are represented like this:
So the Pythagorean Theorem would be:
as the coordinates of point A which is
as the coordinates of point B which is
We substitute the values to the Pythagorean theorem:
Therefore the length of the line segment is