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Grade 4 Math
Target Skill: Polygons
Week of
Curriculum Alignment
Virginia Strand
Geometry: Representations and Polygons
Skill Review
Students will identify and compare polygons with up to ten sides. They
will understand the difference between a regular polygon and an irregular
polygon. Students will also understand that there are different types of
quadrilaterals, and will be able to name and classify them.
Standards of Learning
4.12.a Define polygon.
4.12.b Identify polygons with 10 or fewer sides.
Success Strategies
1. Remind students that a polygon is a closed two-dimensional figure made of three or more line segments.
Draw a square and a triangle on the board. Ask the students if both figures are polygons. (yes) Discuss why.
Then ask the students to come to the board and draw any polygon. Discuss the figures drawn. Tell students
that polygons are named by the number of sides they have. Write this table on the board and ask students
to name the polygon they drew.
2. Draw a regular and an irregular pentagon on the board. Discuss how the two figures are alike and different
(both are pentagons; one has equal sides). Write this definition on the board: A regular polygon has all
sides congruent and all angles congruent. Ask a volunteer to label the regular pentagon. Label the other
example irregular pentagon. Ask students to choose a polygon and to sketch a regular and an irregular
example. Drawings do not have to be exact. Check students’ sketches and ask volunteers to share their work.
Number of
Sides
3
4
5
6
7
8
9
10
Name
of Polygon
triangle
quadrilateral
pentagon
hexagon
heptagon
octagon
nonagon
decagon
3. Draw the following on the board: 1. parallelogram, 2. rectangle, 3. rhombus, 4. square, 5. trapezoid. Ask students to name the figures by
number of sides (quadrilaterals). As a class, classify the figures by those that have 4 right angles (2, 4), all sides equal (3, 4), 2 pairs of
equal sides (1, 2, 3, 4), 1 pair of equal sides (5), 2 pairs of opposite sides parallel (1, 2, 3, 4), and 1 pair of opposite sides parallel (5). Write
parallelogram, rectangle, rhombus, square, and trapezoid on the board. As a class, match each term with a figure.
4. Give short straws of equal and unequal lengths to small groups of students. Each student should model a regular or irregular polygon, then
write its name on a piece of paper. Group members should identify each other’s polygons and see if their decision matches the name on
the paper.
VA Companion Guide
© 2012 EdisonLearning, Inc.
Testing the Skill
The skill of identifying, classifying, and comparing polygons often is tested as follows.
1. Which figure is a regular octagon?
A. Figure 1
B. Figure 2
C. Figure 3
D. Figure 4
2. Which polygon is always both a rectangle and a rhombus?
A. quadrilateral
B. polygon
C. square
D. trapezoid
C. octagon
D. pentagon
3. Which type of polygon has nine sides?
A. decagon
B. nonagon
4. Which quadrilateral always has exactly 1 pair of opposite sides parallel?
A. parallelogram
B. pentagon
C. square
D. trapezoid
5. Follow the clues to answer these questions.
I have two more sides than an octagon has. All of my sides and angles are congruent. Use straws to model me. Who am I?
I have 2 pair of opposite sides parallel, 2 pair of sides equal, and four right angles. Use straws to model me. Who am I? Classify me as many
ways as you can.
Answer Key
1. D
2. C
3. B
© 2012 EdisonLearning, Inc.
4. D
5. See students’ models; regular decagon; polygon, quadrilateral, parallelogram, rectangle