Jim and Lynn were asked to find the coordinates of the midpoint of the segment whose endpoints are R (−15, −8) and S (−5, −2). Jim used point S as ( x 1 , y 1 ). Lynn said he had to use point R as ( x1 , y 1 ). Who is correct? Explain.

Both Jim and Lynn, as midpoint formula observes commutative property, which commutes the position of each endpoint inside the sum without altering the result.

Step-by-step explanation:

We must remember that location of midpoint of any line segment can be determined by using this formula in function of the endpoint locations:

Where:

, - Location of midpoint, dimensionless.

, - Location of endpoint R, dimensionless.

, - Location of endpoint S, dimensionless.

Both Jim and Lynn, as midpoint formula observes commutative property, which commutes the position of each endpoint inside the sum without altering the result. That is: