Algebra
Distance between the two points
The straight-line separation, from Pythagoras. Related to slope but answering a different question.
The Formula
d = sqrt((x2 - x1)^2 + (y2 - y1)^2)
The straight-line separation, from Pythagoras. Related to slope but answering a different question.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| d | Straight-line distance | same as coordinates | Independent of which point you call first, because both differences are squared. |
What Each Symbol Means
dsame as coordinates
Straight-line distance
Independent of which point you call first, because both differences are squared.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate slope page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Slope, filed under Math. Every number the guide produces comes from substituting into this one line.