How do you find the coordinates of the other endpoint of a segment with the given endpoint T(-8,-1) and midpoint M(0,3)?

1 Answer
Jun 15, 2017

Reflect the endpoint around the midpoint.

Explanation:

To do this algebraically, you consider how to get to the midpoint from the endpoint, and then do that move again to get to the other endpoint.

In the x direction, to get from T to M, you need to go #8# in the positive direction.

In the y direction, to get from T to M, you need to go #4# in the positive direction.

Therefore, to get to our other endpoint (let's call it E), we need to make these same moves again.

Move #8# in the positive x direction from M:

#0 + 8 = 8#

Move #4# in the positive y direction from M:

#3 + 4 = 7#

So the other endpoint is #(8,7)#. The following image shows this process graphically:

desmos.com/calculator