1-2 Linear Measure and Precision
A line segment has a measurement which is the length of the
segment.
Depending on the unit of measurement, there will be a range
of accuracy. This is called precision.
Use the ruler to measure the length of the following:
your notebook
your iPhone
your desk
the SmartBoard
the doorway
Let’s find the average of the measurements.
Why might they be different depending on each person?
The precision of a measurement should be accurate within a
half of the smallest available measurement. In other words, if
your ruler only measures in inches, your measurements
should be precise within ½ of an inch.
For example: If you had measured your notebook to be 11
inches, the measure could range anywhere from 10.5 inches
to 11.5 inches (1/2 inch too big or too small)
If something is measured to the nearest ½ inch or centimeter
etc, you should divide the smallest unit by 2 to find the
precision.
Examples:
Find the precision for a measurement of 5 millimeters.
Find the precision for a measurement of 8.5 inches.
Find the precision for a measurement of 10 ¼ inches.
We can add or subtract lengths of segments just as we add or
subtract numerical values. This will be a critical skill
throughout the year.
Betweenness of points means that the length of segment AB
plus the length of segment BC should equal the entire length
of segment AC as long as all three points are collinear.
Examples p. 15
Class Work
p. 17 #1-11
Homework
p. 17 #12-32 evens