MathGeometry & TrigonometryMedium frequency

SAT Math: Midpoint and Distance Formulas

20+ practice questions in Praczo

What you need to know

The concept, explained

  • 1

    Midpoint between (x₁,y₁) and (x₂,y₂): M = ((x₁+x₂)/2, (y₁+y₂)/2).

  • 2

    Distance: d = √((x₂−x₁)² + (y₂−y₁)²). This is the Pythagorean theorem applied to coordinates.

  • 3

    To find the other endpoint when given a midpoint and one endpoint, set up the midpoint formula and solve.

  • 4

    Distance formula gives the straight-line (hypotenuse) length between two points.

  • 5

    Vertical or horizontal distances are simpler: just subtract the coordinates that differ.

Common mistakes
  • Averaging only the x-coordinates and forgetting the y-coordinate for the midpoint.
  • Squaring the subtraction incorrectly: (x₂−x₁)² is not x₂²−x₁².
Try a sample question

SAT-style practice

What is the midpoint of the segment connecting (2, −5) and (8, 3)?

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