INSTRUCTORSCarleen EatonGrant Fraser

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### 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.

## Distance Formula

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