SEGMENT ADDITION

This stuff is AWESOME!

Can you see a shark?What about now?

AB means the line segment with endpoints A and B.

AB means the distance between A and B.

A B

AB = 14 cm

C

D

EG

E is between C and D.G is not between C and D.For one point to be between two other points, the three points must be collinear.

If Q is between P and R, then PQ + QR = PR.

What does this mean?

Start with a picture:P RQ

If point Q is between points P and R, then the distance between P and Q plus the distance between Q and R is equal to the distance between P and R.

If PQ + QR = PR, then Q is between P and R.

What does this mean?

If the measure of segment PQ plus the measure of segment QR is equal to the measure of segment PR, then point Q must be between points P and R.

P RQ

P RQ

PR = 1512 3

14 3

15

COLORED NOTE CARD

Segment Addition Postulate #2

If Q is between P and R, then PQ + QR = PR.

If PQ + QR = PR, then Q is between P and R.

P RQ

N is between L and P. LN = 14 and PN = 12. Find LP.

L PN

Q is between R and T. RT = 18 and QR = 10. Find QT.

R TQ

14 12

18

10

Find MN if N is between M and P, MN = 3x + 2,NP = 18, and MP = 5x.

M PN3x + 2 18

5x

3x + 2 + 18 = 5x 3x + 20 = 5x -3x -3x 20 = 2x 2 2 10 = x

MN = 3 (10 ) + 2MN = 32