When two points have the same x-coordinate, they are on a vertical line. The distance between them is the difference of their y-coordinates. From (2, 3) to (2, −4) the distance is 3 − (−4) = 7 units.
When they have the same y-coordinate, subtract the x-coordinates. If the points are on opposite sides of an axis, add the absolute values: from (−3, 1) to (5, 1) is 3 + 5 = 8 units.
These distances help you find the perimeter of a rectangle drawn on the grid: find each side, then add.
Worked example
How far apart are (4, −2) and (4, 6)?
- Same x-coordinate, so subtract the y-coordinates.
- 6 − (−2) = 8.
Answer:8 units
Key words
- distance
- how far apart, never negative
- vertical
- straight up and down
- horizontal
- straight across
Practise this
New questions every time.
Common Core-referenced: 6.NS.C.8