1. We’re going to grade homework first today Please get it out and be ready when the bell rings. Thanks

2. Measuring Pick 6 strips of paper from the container. Get a ‘ruler’. With your partner, please measure and record the measurements of the items you chose from the bucket. Your measurements need to be as accurate as possible – NOT ESTIMATES.

3. Measuring Length

4. How do you measure distance on a number line? -3 -2 -1 0 1 2 3 4 5 6 7 What is the distance between -2 and 35 What is the distance between -2 and -7 What is the distance between 5 and 17 What is the distance between 0 and -5 What is the distance between 10 and -3 5 12 5 13 Notice that all the DISTANCES ARE POSITIVE! What mathematical operation makes all answers positive? ABSOLUTE VALUE!!!

5. ♥On a number line, the distance between the coordinates a and b is |a-b| or |b-a|. ♥This will give you the measure of the segment. Measuring length a b WRITE THIS DOWN

6. Notation for MEASURE of a segment mXY or XY If you use the bar, use the m. If you don’t use the bar, don’t use the m In this notation, we are talking about the LENGTH of the segment NOT the segment itself. -3 -2 -1 0 1 2 3 4 5 6 7 X Y Z mXY = |-3 - 0| = |-3| = 3 XZ = |-3 - 4| = |-7| = 7

7. CONGRUENT Means the same size and same shape The congruent symbol is = ~ Means the same size and same shape The congruent symbol is = ~ A B C D AB CD ~ = AB C D E

8. Segment Congruence Postulate ♥If two segments are congruent, then they have the same measure. ♥The converse is also true : If two segments have the same measure, then they are congruent. Are you able to write a biconditional? Remember…. A biconditional IS A DEFINITION

9. AB C D E ~ = The converse is also true: If AC = BD then AC BD Important notation If AC BD then AC = BD ~ = This says: if the segments are CONGRUENT then the measures are EQUAL. Without the bar means NUMBER AC is a NUMBER AC is NOT

10. Segment Addition Postulate If point R is between points P and Q, then PR + RQ = PQ P R Q A B C 3 5 AB + BC = AC 3 + 5 = AC 8 = AC X + 3x + 1 = 25 4x + 1 = 25 4x = 24 X = 6 Find the measure of each segment and CHECK YOUR ANSWER A B C x 3x + 1 AC = 25

11. Let’s learn how to BISECT a segment You need 1 piece of patty paper straight edge compass

12. Your assignment 2.2/2.3 packet