9.1 Outline

A.  Introduction
      1. measure 
      2. precision/accuracy
          a. accuracy procedure used in this book
          b. metric world in 2010
B. Measuring length
      1. define length
          a. U.S. system
          b. metric system
      2. standard length units
          a. U.S. system
          b. metric system; prefixes
C. Perimeter
      1. define perimeter
      2. formulas
          a. equilateral triangle
          b. rectangle
          c. square
D.  Circumference
      1. terminology
          a. define circle; radius, diameter, center, semicircle
          b. define circumference
          c. the number pi

9.1 Essential Ideas

To measure an object is to assign a number to its size.

The number representing is linear dimension, as measured from end to end, is called its measure or length.

To measure length, use the following units of measurement:
                     U.S. System                  Metric System
                     inch (in.)                      meter (m)
                     foot (ft; 12 in.)              centimeter (cm; 1/100 m)
                     yard (yd; 36 in.)            kilometer (km; 1,000 m)
                     mi (mi)

The perimeter of a polygon is the sum of the lengths of the sides of that polygon.
The circumference of a circle is the distance around the formula.