The rectangular coordinate system, also known as the Cartesian coordinate system, identifies points based on their x and ycoordinates. When you have two points identified by their coordinates, you can find the distance between the two points using the distance formula, which derives from the Pythagorean theorem. You can form a right triangle with the two points and then use the change in the xcoordinates to find one side and the change in the ycoordinates to find the other side. From there, you can calculate to find the hypotenuse, which measures the distance between the two points.
Things You'll Need
 Calculator

Subtract the first xcoordinate from the second xcoordinate. For example, if your coordinates are (3, 5) and (4, 2), subtract 3 from 4 to get 7.

Subtract the first ycoordinate from the second ycoordinate. For example, if your coordinates are (3, 5) and (4, 2), subtract 5 from 2 to get 3.

Square the differences. In this example, square 7 to get 49 and square 3 to get 9.

Add the squares. In this example, add 49 and 9 to get 58.

Calculate the square root of the Step 4 result to find the distance between the two points. Completing the example, take square root of 58 to find the distance is approximately 7.62.
References
 Photo Credit Jupiterimages/BananaStock/Getty Images