You find the squares it around, say 23, well its between 25 and 16 the pefect square roots of 5 and 4 and 23 is closer to 25 so it would be around 5
-- Find how much 'y' changes from the first point to the second one.
-- Find how much 'x' changes from the first point to the second one.
-- The slope of the line going from the first point to the second one is
(change in 'y') / (change in 'x') .
Okayyyyyyyyyyyyyyyyyyuyyyuyyyyy