Student activity · Grades 8–10 · about 20 minutes

Distance & Midpoint Worksheet

Goal: Find the distance between two points with the Pythagorean theorem, find midpoints by averaging coordinates, and spot horizontal and vertical segments.

Tool: Distance, midpoint & slope at geometrylab.net/tools/coordinate-geometry/ · Connects to Common Core 8.G.B.8

What to do

  1. Open the distance, midpoint & slope tool.
  2. For each pair of points in the table, type the coordinates into “Point A · x”, “Point A · y”, “Point B · x” and “Point B · y”, or drag the points on the grid. Record the distance, midpoint and slope.
  3. For each row, sketch the right triangle whose legs are Δx and Δy.

Record your results

SettingDistanceMidpointSlope
A(0, 0), B(3, 4)
A(−3, −2), B(4, 5)
A(1, 2), B(7, 2)
A(2, −1), B(2, 5)
A(−4, 3), B(2, −5)

Questions

  1. For A(0, 0) and B(3, 4), use Δx, Δy and the Pythagorean theorem to find the distance.

  2. Find the distance from A(−3, −2) to B(4, 5) by hand. Write it as a square root, then round.

  3. How do you find a midpoint without the tool? Show it for A(−4, 3) and B(2, −5).

  4. Two rows have a distance of 6. What is special about these pairs of points, and what are their slopes?

  5. M(4, 2) is the midpoint of segment AB, and A is (1, 2). Find B.

  6. Which pair of points is farthest apart? Show the distance calculation.

Free from Geometry Lab · geometrylab.net · 8.G.B.8: Apply the Pythagorean theorem to find the distance between two points in a coordinate system.

Teaching with this? Find the answer key and more activities on the Geometry Lab for teachers page.