The length of a line segment
Pythagoras's theorem applies to right-angled triangles. The area of the square drawn on the hypotenuse is equal to the sum of the squares drawn on the other two sides. can be used to calculate the distance between two points.
The line between points X and Y is a line segment. A line segment is a part of a line which has two end points.
Example
Point A has the coordinates (3,2).
Point B has the coordinates (11,8).
Calculate the distance AB.
Image caption, First plot the points
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Use Pythagoras' theorem to calculate the distance AB.
\(a^2 + b^2 = c^2\)
\(6^2 + 8^2 = \text{AB}^2\)
\(100 = \text{AB}^2\)
The length of AB is 10.