Page 75 - Math Course 1 (Book 2)

Measurements in Geometry

Mo. 9

Lesson 2 construction

are methods of creating geometric f gures without
the benef t of measuring tools.

KEY CONCEPTS:
1. Measure segments and determine Generally, only straightedge /
accuracy of measurement. ruler, and compass are used.
2. Compute with measures.

MO. 9 - L2a
Let’s Begin

Measurement and Precision

Length in Metric Units
Vocabulary A-Z

Let us learn some vocabulary Examples

A. Find the length of LM

line segment L M
Unlike a line, a line segment, or segment, can be
measured because it has two endpoints.

A B
The long marks are centimeters, and the shorter
marks are millimeters. There are 10 millimeters for
each centimeter.

A segment with endpoints A and B can be named LM
Answer
as AB or BA. is about 42 millimeters long.

precision
The precision of any measurement depends on the B. Find the length of QR
smallest unit available on the measuring tool. The Q R
measurement should be precise to within 0.5 unit
of measure.

The ruler is marked in centimeters. Point R is
closer to the 5-centimeter mark than to 4
centimeters.

If the smallest unit of measure Answer QR
on the tool is centimeters, is about 5 centimeters long.
3 centimeters means that
the actual length is no less
than 2.5 centimeters, but no
more than 3.5 centimeters

67