1. Geometry 2.5 Midpoints

2. Midpoint for number linesA B
The midpoint for AB is found by adding a and b then dividing by 2
A + b 2

3. Midpoint for number lines6 10
The midpoint for AB is found by adding a and b then dividing by 2
6 + 10 2

4. Midpoint for number lines-2 4
The midpoint for AB is found by adding a and b then dividing by 2
-2 + 4 2

5. What if it’s not a flat line?
That’s
why we just
Learned about
The coordinate plane B

6. What if it’s not a flat line?
(x,y) A
We just
need the
X and y coordinates
For each end
(x,y) B

7. That is kind of confusing
(x1,y1)
(x,y) A
We have
Two points
So let’s change
How we label them
(x2,y2)
(x,y) B

8. Here is your formula
( , )
X1 + X2 2
Y1 + Y2 2

9. If this is easier for you
( , )
Add X’s 2
Add Y’s 2

10. (1,8)
( , )
2 2 A
(4, 6)
( , )
X1 + X2 Y1 + Y2
(7,4) B
( , )

11. (-3,6)
( , )
2 2 A
(1, -2)
( , )
X1 + X2 Y1 + Y2
(5,-10) B
( , )

12. MIDPOINT Y1 + Y2 X1 + X2 2 2 (x1,y1) First, We are finding
The middle of the
X’s
Then
We are finding
The middle of the
Y’s
And that
gives us the
MIDPOINT
(x2,y2) B

13. (x3 & x5)

14. x3 & x5 19 20 21 22 23 24 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18