Final answer:
To find the distance between two points on the coordinate plane, calculate the difference in x-coordinates and y-coordinates and use the Pythagorean Theorem.
Step-by-step explanation:
To find the distance between two points using the Pythagorean Theorem on the coordinate plane, we need to determine the difference in the x-coordinates and the difference in the y-coordinates of the two points. For the given points, the x-coordinate difference is (-9) - (-1) = -9 + 1 = -8 and the y-coordinate difference is (-8) - (-4) = -8 + 4 = -4.
Using the Pythagorean Theorem, the distance between the points is √((-8)^2 + (-4)^2) = √(64 + 16) = √80 units. Therefore, option O√80 units is the correct answer.
Learn more about Pythagorean Theorem and the coordinate plane