The distance between two points (x1, y1) and (x2, y2) can be calculated as follows:
[tex]d=\sqrt[]{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]The points are given: (3, 1) and (9, 9), thus:
[tex]d=\sqrt[]{(9-3)^2+(9-1)^2}[/tex]Operating:
[tex]\begin{gathered} d=\sqrt[]{6^2+8^2} \\ d=\sqrt[]{36+64} \\ d=\sqrt[]{100} \\ d=10 \end{gathered}[/tex]The distance is 10