Distance between two points in the Cartesian plane is the length of the line segment joining them, found from the horizontal and vertical coordinate differences using the Pythagorean relationship: . The understanding includes handling negative coordinates, recognizing that reversing the points does not change the distance, and expressing results exactly or approximately, with horizontal and vertical cases as special instances; it is confined to Euclidean two-dimensional coordinates, not three-dimensional or more abstract distance measures.
The distance between two points is the length of the line segment joining them. Use the distance formula:
This formula comes from the Pythagorean theorem: the horizontal difference and vertical difference form the two legs of a right triangle.
Example: Find the distance between and .
Identify the coordinates:
Find the horizontal and vertical differences:
Substitute into the distance formula:
Simplify:
Therefore, the exact distance is
As a decimal, this is approximately
The order of the points does not matter. Reversing them changes the signs of the differences, but squaring makes the final distance the same.
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