The distance d between two points with coordinates is

given by .

This formula can be derived from the Pythagorean Theorem.

First draw a coordinate plane, plot the points X and Y. Form the right triangle

using gridlines.

The measure of segment XY is the hypotenuse of the right triangle.

The Pythagorean Theorem states that the square of the hypotenuse is the sum of

the squares of the legs. Let d ids the distance between points X and Y.

          (Substitute )

        (Take the square of root each side)

From figure; coordinates of S and T are respectively.

Substitute the coordinate values in the midpoint

formula.

                (Product of two same signs is positive) \ \

                          (Add: 6 + 3 = 9)

                                   (Subtract: )

                                    (Evaluate power: )

                                          (Add: 81 + 9 = 90)

                                       (Use calculator to find the value)

                                            (Round to the nearest value)

Distance between two points S and T is about 9.5 units.