To the nearest foot, it would be 23 feet. I found this using the Pythagorean Theorem of a (squared) + b (squared) = c (squared). If you have 24 as the hypotenuse, you have to square this and subtract 64 (8*8) from it. That will equal 512. So you have to find the square root of that which is 22.62, which will round to 23 feet.
To get these, you can subtract 2 from the x-value because they are moving 2 units to the left and add 2 to the y-value because they are moving 2 units up.