Skip to content

Points in the coordinate system

Two points in a coordinate system: how far apart are they, where is the middle, and which line goes through both?

The explanation is shown. Quick: distance, midpoint and the line. Advanced: also angle of inclination, axis intercepts and the points along the segment.

Your numbers

Answer

Distance between the points

10

Midpoint

(1 ; 4)

The line through the points

y = 0.75x + 3.25

xy-10-10-5-5551010ABM

How to work it out

  1. 1Δx = 5 − -3 = 8 · Δy = 7 − 1 = 6
  2. 2|AB| = √(Δx² + Δy²) = √(64 + 36) = 10
  3. 3M = ((-3 + 5) / 2 ; (1 + 7) / 2) = (1 ; 4)
  4. 4a = Δy / Δx = 6 / 8 = 0.75 · b = y₁ − a·x₁ = 3.25

The formula

|AB| = √((x₂ − x₁)² + (y₂ − y₁)²)

The distance formula is Pythagoras: Δx and Δy are the legs.

M = ((x₁ + x₂)/2 ; (y₁ + y₂)/2)

The midpoint is the average of the coordinates.

In depth: more numbers and “what if”

More quantities

SizeValue
Δx8
Δy6
Slope a0.75
Angle of inclination36.9°
Crosses the y-axis at(0 ; 3.25)
Crosses the x-axis at(-4.33 ; 0)
Distance from A to (0 ; 0)3.16
Distance from B to (0 ; 0)8.6

Points on the segment from A to B

Share of the wayPoint
0 %(-3 ; 1)
25 %(-1 ; 2.5)
50 %(1 ; 4)
75 %(3 ; 5.5)
100 %(5 ; 7)

More: Geometry

9