Explanation:
The coordinates are given below as
[tex]\begin{gathered} (x_1,y_1)=(12,-7) \\ (x_2,y_2)=(3,-16) \end{gathered}[/tex]Concept:
To calculate the distance between the points above, we will use the formula below
[tex]D=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]By substituting the values, we will have
[tex]\begin{gathered} \begin{equation*} D=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2} \end{equation*} \\ D=\sqrt{(3-12)^2+(-16-(-7)^2} \\ D=\sqrt{(-9)^2+(-9)^2} \\ D=\sqrt{81+81} \\ D=\sqrt{162} \\ D=\sqrt{81\times2} \\ D=\sqrt{81}\times\sqrt{2} \\ D=9\sqrt{2} \end{gathered}[/tex]Hence,
The final answer is
[tex]\Rightarrow9\sqrt{2}[/tex]