Teaching the Common Core Math Standards With Hands-On Activities, Grades 3-5 (50 page)

8.
Draw a line. Choose a point on the line. Place the crosshatch of the protractor on this point. Place the protractor on the line so that the
line of the protractor is on the line you drew. Mark a point at the
mark near the scale of the protractor. Use your ruler to draw a line through both points.

9.
Mark two points. Use your ruler to connect the points.

Geometry: 4.G.2

“Draw and identify lines and angles, and classify shapes by properties of their lines and angles.”

2. “Classify two-dimensional figures based on the presence or absence of parallel or perpendicular lines, or the presence or absence of angles of a specified size. Recognize right triangles as a category, and identify right triangles.”

Background

Identifying the attributes of geometric figures is an important skill. Two-dimensional figures may be classified in a variety of ways, including by the number of sides, by the measures of their angles, or whether their sides are parallel or perpendicular.

Activity: Drawing Two-Dimensional Figures

Students will draw two-dimensional figures according to their attributes.

Materials

Ruler; protractor; unlined paper; reproducible, “Figures,” for each student.

Procedure

1.
Review examples of two-dimensional figures: quadrilaterals, squares, rectangles, parallelograms, trapezoids, right triangles, acute triangles, obtuse triangles, pentagons, and hexagons. Also, review the terms: acute angle, obtuse angle, right angle, and congruent.

2.
Explain that two-dimensional figures can be classified by their various attributes, such as the number of their sides, the type of their angles, and the presence of parallel or perpendicular lines.

3.
Hand out copies of the reproducible. Explain that it contains attributes for nine figures. Based on the attributes, students are to draw the figures. You may also ask them to name the figures they have drawn.

4.
Instruct your students to use rulers and protractors when drawing their figures. These tools will help ensure the accuracy of their drawings. If necessary, review the steps for drawing angles with a protractor.

Closure

Check the figures your students drew. Allow students to share their figures with some of their classmates. Discuss that in some cases a variety of different figures can be drawn that will share the same attributes.

Answers

Student figures may vary; some attributes describe more than one figure.
(1)
Trapezoid
(2)
Rhombus
(3)
Right triangle
(4)
Obtuse triangle
(5)
Various quadrilaterals, except parallelograms, rhombuses, rectangles, and squares
(6)
Acute triangle
(7)
Rectangle, square (a square is a special kind of rectangle)
(8)
Square
(9)
Parallelogram

Figures

Directions: Draw each figure based on its attributes.

1.
This quadrilateral has two parallel sides. The other two sides are not parallel.

2.
This quadrilateral has four congruent sides. It has no right angles.

3.
This triangle has two perpendicular sides.

4.
This triangle has one obtuse angle.

5.
This quadrilateral has no right angles. No sides are parallel.

6.
This triangle has three acute angles.

7.
This quadrilateral has four right angles.

8.
This quadrilateral has four congruent sides. It has four right angles.

9.
This quadrilateral has no right angles. Its opposite sides are parallel and congruent. All four sides are not congruent.

Geometry: 4.G.3

“Draw and identify lines and angles, and classify shapes by properties of their lines and angles.”

3. “Recognize a line of symmetry for a two-dimensional figure as a line across the figure such that the figure can be folded along the line into matching parts. Identify line-symmetric figures and draw lines of symmetry.”

Background

If a figure folds along a line so that half of the figure entirely covers the other half, and the two parts are congruent, the figure has line symmetry. Following are some examples:

Activity 1: Line Symmetry

Students will play a game on a Web site where they will state the number of lines of symmetry of various polygons.

Materials

Computers with Internet access for students; computer with Internet access and digital projector for the teacher.

Procedure

1.
Explain that students will play “Symmetry Game” at a Web site. They will find the number of lines of symmetry of polygons displayed on the screen.

2.
Instruct your students to go to
www.innovationslearning.co.uk/subjects/maths/activities/year3/symmetry/shape_game.asp
. On the screen they will see the introduction to the game.

3.
Demonstrate how the game works by clicking “Start.” A figure will appear. Ask a volunteer how many lines of symmetry the figure has. Write that number in the white box and click on “Enter.” If the number is correct, students will see the message “Great Job,” and they will receive 10 points. They should click on “Next Shape” to continue. If they are incorrect, they will see the message “So Close,” and they will lose 5 points. In this case, they will see the figure folding along the lines of symmetry. After writing the correct answer, they should click on “Next Shape.” Note that the game consists of 10 figures.

4.
Start the game; challenge your students to score 100 points.

Closure

Ask your students questions such as the following: Which of the figures had the most lines of symmetry? Which had the least? Did you find any patterns in the lines of symmetry of the various shapes? If yes, what were they? Instruct students to write a short explanation of line symmetry.

Activity 2: Classroom Line Symmetry

Working in pairs or groups of three, students will identify two-dimensional figures in the classroom that have line symmetry.

Materials

Unlined paper for sketching figures for each pair or group of students.

Procedure

1.
Explain that many two-dimensional figures have line symmetry. For example, a rectangular bulletin board has two lines of symmetry. Note the example of the rectangle provided in the Background.

2.
Explain that students are to identify at least five two-dimensional figures in the classroom that have line symmetry. They are to sketch the figures and draw the lines of symmetry.

Closure

Ask for volunteers to share their figures and the number of lines of symmetry of each with the class. Verify that students are correct.