Section 1-2 - Linear Measure and Precision
A. Definitions
1. A line segment can be measured because it has two ___________________.
a. A segment with endpoints A and B can be written AB .
b. The distance between points A and B is written AB (with no line
above it..
Example 1: Find the length of CD using each ruler.
a.)
C
D
0 cm 1
2
3
4
5
CD = ________________ (which reads “the length between points C and D =”)
C
D
b.)
0cm 1
2
3
4
5
6
CD = _________________
c)
C
0 in
D
1
2
CD = __________________
2. Precision of any measurement depends on the smallest unit available on the
measuring tool.
a. The measurement should be precise to within ________ unit of
measure
b. For example, in example 1, letter a, 4 centimeters means the actual
length is between 3.5 and 4.5 centimeters.
Example 2: Find the precision for each measurement. Explain its meaning.
3
a.) 32 inches
4
b.) 15 millimeters
Example 3: Find the measurements.
L
a.) Find LM
N
2.5 cm
M
4 cm
LM = ____________
b.) Find XZ
X
4
5
8
Y
2
1
2
Z
XZ = ____________
c.) Find x and ST if T is
Between S and U, ST = 7x ,
SU = 45, and TU = 5 x − 3 .
U 5x − 3
T
7x
S
x = ________
ST = ________
3. If two segments are the same length they are said to be congruent segments.
a.) This is represented on a drawing by an equal number of slashes on the
congruent segments.
HW
Geom 1-2 p. 17-19
12-15, 16-32 even, 34-39, 56-65