Since the y-coordinate is the same. Therefore, there is a straight horizontal line between the two points. So, again, since the y-coordinates are the same, we can subtract C(x) (the x-coordinate for point C) from D(x) (the x-coordinate for point C)
C(x) = 3.5
D(x) = 0.5
3.5 - 0.5 = 3
Therefore, the distance between the two points is 3 units
