The distance is the length between two points. The formula for distance is [math]d=\sqrt{\left(X2-X1\right)^2+\left(Y2-Y1\right)^2}[/math]

To find the distance of AB using the toolbar, click on the icon with an angle and click on distance. After that, click on the two points.

Another way is to use the distance formula. To do that, put the x-coordinate for point B where X2 is. Put the y-coordinate for point B where Y2 is. The x-coordinate for point A goes in the place of X1. The y-coordinate for point A goes in the place of Y1. So far you should have [math]d=\sqrt{\left(5-1\right)^2+\left(4-1\right)^2}[/math]. Now, do the math in the parentheses. Now you should have [math]d=\sqrt{4^2+3^2}[/math]. The exponents make it [math]d=\sqrt{16+9}[/math]. After you add 16 and 9, you get [math]d=\sqrt{25}[/math]. 25 is a perfect square so the distance is 5.