Describing Geometric Solids

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This pdf covers comparing and creating geometric solids. In mathematics, solid geometry or stereometry is the traditional name for the geometry of three-dimensional, Euclidean spaces. Stereometry deals with the measurements of volumes of various solid figures, including pyramids, prisms, and other polyhedrons; cylinders; cones; truncated cones, and balls bounded by spheres.
1. Objective To review the properties of common geometric solids.
1 Teaching the Lesson materials
Key Activities  Math Journal 2, pp. 289 and 290
Students review common geometric solids—including prisms, pyramids, cylinders, cones,  Student Reference Book, p. 101
and spheres—and investigate their properties.  Study Link 11 1

Students construct rectangular prisms using straws and twist-ties.  models of geometric solids (See
Planning Ahead in Lesson 11 1.) 
Key Concepts and Skills
 straws and twist-ties
• Identify parallel and intersecting line segments and parallel planes. [Geometry Goal 1]
 Class Data Pad (optional)
• Describe, compare, and classify plane and solid figures. [Geometry Goal 2]
• Identify congruent faces. [Geometry Goal 2] See Advance Preparation
• Construct a rectangular prism. [Geometry Goal 2]
Key Vocabulary
geometric solid • rectangular prism • cylinder • triangular prism • cone • sphere • square
pyramid • face • congruent • curved surface • edge • vertex (vertices) • cube • flat surface
Ongoing Assessment: Recognizing Student Achievement Use journal page 290.
[Geometry Goal 2]
2 Ongoing Learning & Practice materials
Students determine how many of each U.S. coin are needed to make a 1-ounce weight.  Math Journal 2, pp. 291 and 292
Students practice and maintain skills through Math Boxes and Study Link activities.  Study Link Master (Math Masters,
p. 328)
 balance or scale capable of
measuring 1 ounce
 pennies, nickels, dimes, and
quarters
3 Differentiation Options materials
ENRICHMENT EXTRA PRACTICE ELL SUPPORT  Teaching Aid Masters (Math
Masters, pp. 389 and 390)
Students explore the Students use a Venn Students create a Word Wall
 models of geometric solids
relationships among the diagram to compare of geometry vocabulary.
number of vertices, faces, geometric solids.  computer with Internet access
and edges of polyhedrons.
Additional Information
Advance Preparation For Part 1, construct a cube with 16 twist-ties and 12 straws, all the Technology
same length. In four boxes, place enough twist-ties and full-size, 1 -size, and 3 -size straws Assessment Management System
2 4
that each pair of students can have 16 twist-ties and 8 straws of each length. Journal page 290, Problem 8
See the iTLG.
See the Web site on page 859.
854 Unit 11 3-D Shapes, Weight, Volume, and Capacity
2. Getting Started
Mental Math and Reflexes Math Message
Write large numbers on the board, and have volunteers read Complete journal page 289.
them aloud. Suggestions:
7,540,312 43,290,517 1,206,598,346
2,560,371 831,247,906 2,165,307,498 Study Link 11 1 Follow-Up 
16,436,280 372,815,206 172,039,598,563
Ask small groups of students to compare
Ask questions like the following: answers and to pose and solve the problems
• What is the value of the digit x? they created.
• Which digit is in the millions place?
1 Teaching the Lesson
 Math Message Follow-Up WHOLE-CLASS
ACTIVITY
(Math Journal 2, p. 289)
Display models of the six geometric solids—rectangular
prism, cylinder, triangular prism, cone, sphere, and
square pyramid—shown on journal page 289.
Begin with the rectangular prism. To support English language
learners, attach a tag and label it. Hold it up and ask the class to
share examples of rectangular prisms in the classroom. You may
wish to keep a list on the board or the Class Data Pad. Repeat this
procedure for the remaining solids.
When all of the solids have been discussed, ask students the
following questions:
Student Page
● Which solids were easy to find? Probably the rectangular prism, Date Time
cylinder, and sphere LESSON
11 2  Geometric Solids
Geometric shapes like these 3-dimensional ones are also called geometric solids.
● Which were hard to find? Probably the pyramid, triangular 101 102
prism, and cone

Rectangular Cylinder Triangular Cone Sphere Square
Why do you think some solids are more common than others? Prism Prism Pyramid
Probably because they are easier to make or are more useful for Look around the classroom. Try to find examples of the geometric solids pictured
above. Draw a picture of each. Then write its name (for example: book).Answers vary.
storing things Example of rectangular prism: Example of cylinder: Example of triangular prism:
Rectangular Cylinder Triangular Cone Sphere Square Name of object: Name of object: Name of object:
Prism Prism Pyramid
Geometric solids Example of cone: Example of sphere: Example of square pyramid:
Name of object: Name of object: Name of object:
289
Math Journal 2, p. 289
Lesson 11 2 
855
3. Student Page
Geometric Solids
Geometry and Constructions
 Reviewing Vocabulary for WHOLE-CLASS
DISCUSSION
Polygons and circles are flat, 2-dimensional figures. The
surfaces they enclose take up a certain amount of area, but
they do not have any thickness and do not take up any volume. face
Geometric Solids
Three-dimensional shapes have length, width, and thickness.
They take up volume. Boxes, chairs, and balls are all examples. face
(Math Journal 2, p. 289; Student Reference Book, p. 101)
face
A geometric solid is the surface or surfaces that surround a
3-dimensional shape. The surfaces of a geometric solid may be cube
flat or curved or both. A flat surface of a solid is called a face.
A curved surface of a solid does not have any special name.
Use the display models of the six geometric solids and Student
A cube has 6 square faces that are the same size. Three of the
cube’s faces cannot be seen in the figure at the right.
face
Reference Book, page 101 to review vocabulary associated with
A cylinder has 3 surfaces. The flat top and flat bottom are
faces that are formed by circles. A curved surface connects the curved
geometric solids. To support English language learners, discuss
top and bottom faces. A food can is a good model of a cylinder.
A cone has 2 surfaces. The flat bottom is a face that is formed
surface
face
the meaning of each term. Pose questions like the following:
by a circle. A curved surface is connected to the bottom face and cylinder
comes to a point. An ice cream cone is a good model of a cone. ● Which of these geometric solids has 6 faces? Rectangular
However, keep in mind that a cone is closed; it has a “lid.”
The edges of a geometric solid are the line segments or curves
where surfaces meet. A corner of a geometric solid is called a
prism
curved
vertex (plural vertices). A vertex is usually a point at which surface

edges meet, but the vertex of a cone is an isolated corner. It is
completely separated from the edge of the cone.
face
Which solids have congruent faces? Rectangular prism,
cone
vertex
edges vertices
vertices
edge
no vertices
cylinder, triangular prism, square pyramid
edges edge
● Which solids have a curved surface? Sphere, cone, and
edge
A sphere has one curved surface but no edges and no vertices. sphere
no edges, no vertices
cylinder
A basketball or globe is a good model of a sphere.
Check Your Understanding ● Which has the most edges? Rectangular prism
1. a. How are cylinders and cones alike? b. How do they differ?
2. a. How are spheres and cones alike? b. How do they differ?
Check your answers on page 343.
● Which two have the fewest vertices (corners)? Cylinder and
Student Reference Book, p. 101 sphere What is the singular form of the word vertices? vertex
● Which has two faces and one curved surface? cylinder
Have students look around the classroom and point out the faces,
edges, and vertices of objects that have shapes similar to those in
the display.
Links to the Future
Encourage students to use the geometry vocabulary, but do not expect them to
be precise at this time.
Student Page  Modeling Geometric Solids PARTNER
ACTIVITY
Date Time (Math Journal 2, p. 290)
LESSON
11 2  Modeling a Rectangular Prism 101 102
After you construct a rectangular prism vertices
Show the class the cube you constructed out of straws. (See
with straws and twist-ties, answer
the questions below.
edges
Advance Preparation.) Point out that it shows only the edges of
the faces. It is a “frame” for the geometric solid; the flat surfaces
faces
of the cube must be imagined.
1. How many faces does your rectangular prism have? 6 face(s)
2. How many of these faces are formed by rectangles? 6 face(s)
3. How many of these faces are formed by squares? 0, or 2 face(s)
4. Pick one of the faces. How many other faces are parallel to it? 1 face(s)
5. How many edges does your rectangular prism have? 12 edge(s)
6. Pick an edge. How many other edges are parallel to it? 3 edge(s)
7. How many vertices does your rectangular prism have? 8 vertices
8. Write T (true) or F (false) for each of the following statements about the rectangular prism
you made. Then write one true statement and one false statement of your own.
a. T It has no curved surfaces. 
b. F All of the edges are parallel.
c. T All of the faces are polygons.
d. F All of the faces are congruent.
e. True Answers vary.
f. False Answers vary.
290
Math Journal 2, p. 290
856 Unit 11 3-D Shapes, Weight, Volume, and Capacity
4. Ask students what geometric solid this construction represents.
Cube, or rectangular prism Demonstrate how the vertices are
put together.
Cube made out of straws and twist-ties
Distribute straws and twist-ties. (See Advance Preparation.) Have
partners work together to make a rectangular prism. One way is
to start with a rectangle and build up. Have the straw cube, as well
as other models of rectangular prisms, available for inspection.
When their rectangular prism is finished, partners should
complete journal page 290.
NOTE Problem 3 on journal page 290 asks students to identify the number of
square faces in the rectangular prisms they have made. Depending on the straw
sizes used, the prisms will have either 0 or 2 square faces. Students cannot
construct cubes (which have 6 square faces) because they have only 8 straws
of each length per partnership.
Journal
Ongoing Assessment:
Recognizing Student Achievement
page 290
Problem 8

Use journal page 290, Problem 8 to assess students’ ability to describe a
rectangular prism. Students are making adequate progress if they are able to Student Page
correctly identify the given statements as true or false and write their own true Date Time
and false statements. Some students may write statements that involve LESSON
comparisons among geometric solids. 11 2  Making a 1-Ounce Weight 140
1. Estimate how many of each coin you think it will take to make a 1-ounce weight. Then use a
[Geometry Goal 2] balance or scale to determine exactly how many of each coin are needed.
Coin Estimated Number Actual Number
of Coins of Coins
penny Answers vary. 11 or 12
nickel 5 or 6
dime 12 or 13
quarter 5
2 Ongoing Learning & Practice 2. Describe how you estimated how many of each coin it might take to make a 1-ounce weight.
Sample answer: I know there are about 28 g in 1 ounce, and
a nickel weighs 5 g. Therefore, 6 nickels should weigh 30 g
(5  6  30), so 6 nickels equal about 1 ounce. I estimate that
1
pennies weigh 2 as much as nickels, so it should take twice as
 Making a 1-Ounce Weight SMALL-GROUP
ACTIVITY
many pennies, which is 12. Dimes are smaller than pennies,
so I guessed 15 dimes. Quarters are heavier than nickels,
so I guessed 4.
(Math Journal 2, p. 291)
Try This
3. About what fraction of an ounce does each coin weigh? Sample answers:
1 1 1 1
   
Students use a balance or scale to determine how many of each 1 penny  12 oz 1 nickel  6 oz 1 dime  13 oz 1 quarter  5 oz
available type of U.S. coin are needed to make a 1-ounce weight. Explain how you found your answers.
Sample answer: I used the number of coins that equal 1 oz
Students can display the results of their experiments in the Gram as the denominator. For example, because 12 pennies equal
1
1 oz, 1 penny equals 12 oz.
& Ounce Museum.
291
Math Journal 2, p. 291
Lesson 11 2 
857
5. Student Page
 Math Boxes 11 2
Date Time

INDEPENDENT
LESSON
11 2  Math Boxes ACTIVITY
1. The object below has the shape of a 2. Draw the figure after it is rotated
(Math Journal 2, p. 292)
1
geometric solid. What is the name of the clockwise 4-turn.
solid? Circle the best answer.
A. rectangular prism Mixed Practice Math Boxes in this lesson are linked
B. cone
with Math Boxes in Lessons 11-4 and 11-6. The skills
C. cylinder
D. square pyramid
VOLUME
0 2 4 6 8 10
in Problems 5 and 6 preview Unit 12 content.
Writing/Reasoning Have students write a response to the
101 102 106 107
3. Write a number model to estimate the 4. Insert , , or  to make a true number
answer. Then correctly place the
decimal point.
sentence. following: For Problem 6, how would you determine the
 1
.
a. 0.97  4  3 8 8
a. 12 19 number of calories in 32 bagels? Sample answer: Multiply

Number model: 144
b. 44

26
the number of calories in 1 bagel by 3; 230 * 3  690. Then divide
c. 64 0.43
.
b. 1 8 7  74.8  4
1
d. 2 
4

the number of calories in 1 bagel by 2; 230 / 2  115. Add the
80  4  20 8
quotient to the number of calories in 3 bagels; 115  690  805.
Number model:
e. 0.28  0.37
6 60
5. Round each number to the nearest tenth. 6. A cinnamon raisin bagel has about
230 calories. How many calories are
a. 2.34 2.3 in one dozen bagels?
b. 0.68
c. 14.35
0.7
14.4
About 2,760 calories
 Study Link 11 2 
INDEPENDENT
ACTIVITY
d. 1.62 1.6 (Math Masters, p. 328)
e. 5.99 6.0
182 183 47
Home Connection Students identify geometric solids
292
Math Journal 2, p. 292 represented by various objects. They also identify the
vertices and the number of edges in two geometric solids.
Study Link Master
Name Date Time
STUDY LINK
11 2  Solids
1. The pictures below show objects that are shaped approximately like
geometric solids. Identify each object as one of the following: cylinder, 101 102
cone, sphere, triangular prism, square pyramid, or rectangular prism.
a. b. c.
Type: square Type: cone Type: sphere
pyramid
d. e. f.
Type: cylinder Type: rectangular Type: triangular
prism prism
2. Mark Xs on the vertices of the 3. How many edges does the
rectangular prism. tetrahedron have? 6 edges
Practice
4. Circle the numbers that are multiples of 7. 132 7,000 63 560 834 91
5. Circle the numbers that are multiples of 12. 24 120 38 600 100 75
Math Masters, p. 328
858 Unit 11 3-D Shapes, Weight, Volume, and Capacity
6. Teaching Aid Master
Name Date Time
3 Differentiation Options Venn Diagram
INDEPENDENT
ENRICHMENT ACTIVITY
 Exploring Euler’s 15–30 Min
Polyhedral Formula
(Math Masters, p. 389)
Technology Link To apply students’ ability to describe solid
figures, have them explore the relationships among vertices,
edges, and faces of polyhedrons at http://nlvm.usu.edu/en/nav/
frames_asid_128_g_2_t_3.html?openinstructions.
On an Exit Slip, ask students to record their observations and draw
a conclusion. Sample answer: The sum of the numbers of faces and
vertices is 2 more than the number of edges: E  2  F  V.
Euler’s polyhedral formula states that the number of vertices
minus the number of edges plus the number of faces is always Math Masters, p. 390
equal to 2.
VEF2
NOTE The Web site is part of the National Library of Virtual Manipulatives
for Interactive Mathematics developed by Utah State University. See
http://nlvm.usu.edu.
INDEPENDENT
EXTRA PRACTICE ACTIVITY
 Comparing Geometric Solids 5–15 Min
(Math Masters, p. 390)
To practice comparing the attributes of solid figures, have
students choose two geometric solids and use them to
complete the Venn diagram on Math Masters, page 390.
SMALL-GROUP
ELL SUPPORT ACTIVITY
 Creating a Word Wall 30+ Min
To provide language support for geometry vocabulary, have
students illustrate definitions of key geometric terms for a
classroom display.
NOTE It might appear that there is an overwhelming number of geometry
terms to know and understand. Each of these terms should be discussed in the
context of solving problems and should relate to students’ experiences. Teaching
these terms in isolation or reducing them to a vocabulary list that needs to be
memorized will not produce successful results in most cases. Students should
have opportunities to work with each of these terms, build models of them, write
them, and discuss them.
Lesson 11 2

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