The distance between the points (x1, y1) and (x2, y2) is computed as follows:
[tex]d=\sqrt[]{(x_1-x_2)^2+(y_1-y_2)^2}[/tex]
Substituting with the points A(1,3) and B(4,7)
[tex]\begin{gathered} d=\sqrt[]{(1-4)^2+(3-7)^2} \\ d=\sqrt[]{(-3)^2+(-4)^2} \\ d=\sqrt[]{9+16} \\ d=\sqrt[]{25} \\ d=5 \end{gathered}[/tex]
The length of the straight line AB is 5 units
