1. Midpoint and Distance in the Coordinate Plane
Name
Class/Period
Date
Midpoint and Distance in the Coordinate Plane
Objective: To find the midpoint of a segment.
Bell Ringer: What does it mean to bisect something? What do you call the point where a segment is bisected?

2. Vocabulary
The point where a segment is bisected is called the midpoint.
On a number line: The coordinate of the midpoint is the average or mean of the coordinates of the endpoints.
The coordinate of the midpoint M of line AB is (a + b) / 2.
In the coordinate plane: The coordinates of the midpoint are the average of the x-coordinates and the average of the y-coordinates.
Given line AB where A(x1, y1) and B(x2, y2), the coordinates of the midpoint of AB are M( (x1 + x2) / 2 , (y1 + y2) / 2 )

3. Example
The midpoint of CD is M(-2, 1). One endpoint is C(-5, 7). What are the coordinates of the other endpoint D?
We know that -2 will be halfway between -5 and D’s x- coordinate.
= 3 So = 1
We know that 1 will be halfway between 7 and D’s y- coordinate.
1 – 7 = -6 So 1 – 6 = -5
So our point D is D(1, -5)

4. Exit Ticket
No exit ticket today .
Homework
P. 60 #5-25 odd