1. 1.2 Linear Measure and Precision Objectives: Measure segments and determine accuracy of measurement. Compute with measures.

2. Line Segment (segment) Portion of a line with two endpoints Labeled without arrowheads: AB Can be measured since it has endpoints Include units of length when measuring

3. Check out p. 17 #1-4 1. 1.3 cm or 13 mm 3.5 cm or 35 mm 2.1 ¾ in. 4. 1 7/8 in.

4. Assignment Pp. 17-18 #12-48 Do #12 – 15 now

5. Precision Describes how accurate a measuring tool is For the tape measure, the smallest unit was 1/16 th of an inch For the metric ruler, the smallest unit was 0.1 cm = 1 mm

6. Precision (con’t) If we measure using the metric ruler, and get a length of 4.7 cm, this means the precision = 0.05 cm and the actual length is somewhere between 4.65 cm and 4.75 cm If we get a length of 12 ½ inches using the tape measure ( ½ = 8/16), then the actual length is between 12 15 / 32 and 12 17 / 32

7. Do #16 – 21 now

8. Betweenness of Points M is between P and Q if PM + MQ = PQ P MQ

9. Find AC AC = AB + BC = 3.3 + 5.2 AC = 8.5 cm ACB 3.3 cm5.2 cm

10. Find y and QP if P is between Q and R, QP = 2y, QR = 3y + 1, and PR = 21. 2y + 21 = 3y + 1 -2y -2y 21 = y + 1 -1 -1 20 = y QP = 2y = 2(20) = 40 QPR 2y21 3y + 1

11. Now do #22 - 48