What you’ll learn
Find polygon side lengths from coordinates.
Key idea
Axis-parallel side lengths use the nonnegative difference of the changing coordinate.
Use the varying coordinate and a nonnegative difference; endpoint direction is an additional construction constraint, not implied by distance alone.
Worked example
Enter the exact value or ordered values in the format requested below.
This coordinate polygon joins A-B-C-D-A. Find the numerical length of AD.
Marked coordinates: D=(-3, -1); C=(2, -1); A=(-3, -3); B=(2, -3).
- The side is vertical; its x coordinate stays fixed.
- Its length is the absolute y change, 2 grid units.
Answer: 2
Quick Check
Relate the graph used in 'Find polygon side lengths from coordinates' to an equation, table, transformation, or verbal description.
The plotted polygon side from (-3, -2) to (2, -2) is horizontal; its other dimension is 2. Choose the coordinate-difference statement explaining the side length.