Why do equivalent ratios form a straight line when graphed? The vertical distance between points is constant, and the horizontal distance between points increases with each point. The ratio of the change in y-values to the change in x-values is equivalent for any two points in a graph of equivalent ratios. The horizontal distance between points is constant, and the vertical distance between points increases with each point. The y-values of equivalent ratios increase at a constant rate, and the x-values decrease at a constant rate.