Let
The coordinate of the midpoint of
Which Midpoint Formula do you use?
If the endpoints are real numbers, use the formula for the number line. If they are ordered pairs, use the formula for the coordinate plane.
Let E(7, 5) be
The coordinates of the midpoint of
When you know the midpoint and an endpoint of a segment, you can use the Midpoint Formula to find the other endpoint.
The midpoint of
How can you find the coordinates of D?
Use the Midpoint Formula to set up an equation. Split that equation into two equations: one for the x-coordinate and one for the y-coordinate.
Let
The coordinates of D are