Polygons, Angles,
and Circles
CHAPTER
1
Real-Life Math
Contents in Brief
1.1 Patterns in Geometry
4
1.2 Angles
24
1.3 Measure Around
40
Review & Self-Assessment
52
This chapter begins by identifying some of the many places
we see polygons, angles, and circles in sports. It explains how
quadrilaterals, spheres, and cylinders are used in various sports,
and how angles of revolution are used in skateboarding.
Think About It
Choose a sport or game and describe how geometry is used in that
sport or game.
What other examples in sports or in a game can you think of that
involve angles? Explain.
Connections to the Past (Grade 5)
Throughout this chapter, you will identify polygons based on the
number of angles and sides they have. List all the shapes you can
think of, and the number of sides each has.
2
Investigation Notebook and Reflection Journal
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Suppose you wanted to build a skateboard ramp. Why would its
shape matter?
Vocabulary
Determine whether each statement refers to polygons (P) or
circles (C).
▼
A two-dimensional closed geometric figure with at
least one angle measuring 180° is concave.
▼
These figures are named according to the number
of sides and vertices each has.
▼
Circumference can be calculated using the formula
C = 2πr.
▼
P or C
A diameter is a chord that passes directly through
this figure’s center.
▼
Statement
When these figures have sides that are all the same
length and angles that are all the same size, they are
called regular.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Family Letter
Which shapes did you find on your walk? What shapes did you
find that you were not expecting to see? Draw some of the shapes
you saw below.
Shapes I saw:
What figures did you see in the building or house? Why do you
think the building is shaped the way it is?
Chapter 1 Opener
3