The midpoint of a segment can be considered to be the average of its endpoints.  This concept helps in remembering a formula for finding the midpoint of a

segment, given the coordinates of its endpoints.  Below is the midpoint formula:

(Picture by Edward Kohn, M.S.-Cliff Quick Review Algebra 11)

Fill in the points into the midpoint formula, and that will give you the midpoint.  For example, R is

the midpoint between points Q(-9,-1) and T(-3,7).