Answer:
[tex]\large\boxed{\sqrt{10}}[/tex]
Step-by-step explanation:
The formula of a distance between two points
[tex](x_1,\ y_1)[/tex] and [tex](x_2,\ y_2)[/tex]:
[tex]d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]
We have two points (2, 8) and (-1, 9).
Substitute:
[tex]d=\sqrt{(-1-2)^2+(9-8)^2}=\sqrt{(-3)^2+1^2}=\sqrt{9+1}=\sqrt{10}[/tex]
