## Lesson goal: The distance formula

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One of the first actual uses of the square root in math is in the distance formula, which is $$d=\sqrt{(x-x_0)^2+(y-y_0)^2}.$$ This formula will tell you the "straight line" distance between any two points on a cartesian coordinate system. As this formula is stated, one point will be $(x,y)$ and the other will be $(x_0,y_0)$. For example, if one point is at $(5,3)$ and the other point is at $(-3,17)$, the distance between them will be $d=\sqrt{(5-(-3))^2+(3-17)^2}$.

In this lesson, we'll see if you can program in the distance formula and have the computer calculate distances for you.