Educator

Distance Formula

• The Distance formula asserts that the distance between the points (x₁, y₁) and (x₂, y₂) in the coordinate plane is √(x₂ – x₁)² + (y₂ – y₁)². This formula is a special case of the Pythagorean theorem.

• Make sure that you know and understand how to use this formula. It will be used in a lot of later work.

• In the Distance formula, the order of the x coordinates does not matter. So take whichever difference is easier to compute. The same comment applies to the y coordinates.

• After squaring the differences in the distance formula, be sure to take the positive square root of their sum.

• In some problems, you are given the distance between two points and three of their coordinates. In this situation, use the Distance formula to find the fourth coordinate.