he Distance between two points is defined as the shortest length between them.

More About Distance

Distance is a scalar quantity.

Example Of Distance

The line joining the open and closed books is a vertical line.
The length of a vertical line-segment on a coordinate plane equals the difference between the y-coordinates.
So, the distance between the two books = 20 - 5 = 15 units.

Video Examples: Algebra - Distance Formula (not upside down)

Solved Example on Distance

Ques: Find the distance between the two points A and B.

Choices:

A. 6 units
B. 8 units
C. 4 units
D. 2 units
Correct Answer: A

Solution:

Step 1: The line joining the two points A and B is a horizontal line-segment.
Step 2: The length of a horizontal line-segment on a coordinate plane equals the difference between the x - coordinates.
Step 3: Point A is located at the ordered pair (2, 4) and point B is located at the ordered pair (8, 4).
Step 4: So, the distance between the two points A and B = 8 - 2 = 6. [Difference between the x - coordinates.]
Step 5: The distance between the two points A and B is 6 units.