Answer:
Length of AB = 10
Explanation:
This can be found by using the distance formula.
Distance Formula =

Where
(x_1,y_1) is the first coordinate pair and (x_2,y_2) is the second coordinate pair
Thus
x_1 = 9 and y_1 = 18
x_2 = 1 and y_2 = 12
Plugging them into the formula, we get:
Length =
. WHich is equal to 10.
Length is 10