Distance formula: $d = \sqrt{(x_2x_1)^2+(y_2y_1)^2}$
Distance formula: $d = \sqrt{(x_2x_1)^2+(y_2y_1)^2}$
In this lesson, we will learn how to use the distance formula to calculate the distance between two points on a graph when you know the coordinates of both points. Distance formula is actually derived from a very basic concept that we learned in geometry: Pythagorean Theorem, ${a^2} + {b^2} = {c^2}$.
Basic concepts:
 Horizontal and vertical distances
 Understanding graphs of linear relationships
 Reading linear relation graphs
Related concepts:
 Pythagorean theorem
 Applications of linear relationships
Lessons

1.
Determine the distance between each pair of points.