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Work Shown:
The two points we have are [tex](x_1,y_1) = (2,1.2)[/tex] and [tex](x_2,y_2) = (2,2.5)[/tex]
Apply the distance formula
[tex]d = \sqrt{(x_1-x_2)^2+(y_1-y_2)^2}\\\\d = \sqrt{(2-2)^2+(1.2-2.5)^2}\\\\d = \sqrt{(0)^2+(-1.3)^2}\\\\d = \sqrt{0+1.69}\\\\d = \sqrt{1.69}\\\\d = 1.3\\\\[/tex]
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A shortcut is possible by subtracting the y coordinates of the two points, and making the result positive through the use of absolute value.
So we either say
|y1-y2| = |1.2-2.5| = |-1.3| = 1.3
or,
|y2 - y1| = |2.5 - 1.2| = |1.3| = 1.3
We get the same result. This shortcut is valid because the x coordinates of both points are the same.