If a(9 18) and B(1 12) what is the length of AB?

To find the length of segment AB between points A(9, 18) and B(1, 12), you can use the distance formula:

[ AB = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} ]

Substituting in the coordinates, we get:

[ AB = \sqrt{(1 - 9)^2 + (12 - 18)^2} = \sqrt{(-8)^2 + (-6)^2} = \sqrt{64 + 36} = \sqrt{100} = 10. ]

Thus, the length of AB is 10 units.