Harrington, Carla. Alexander County Public Schools, Teacher.
Mathematical Concept: Rotation
Grade Levels: 7th – 8th
NCTM Standards and Principles of School Mathematics:
• Understand relationships among the angles, side lengths, perimeters, areas, and volumes of similar objects.
• Create and critique inductive and deductive arguments concerning geometric ideas and relationships, such as congruence, similarity, and the Pythagorean relationship.
• Use geometric models to represent and explain numerical and algebraic relationships.
• Recognize and apply geometric ideas and relationships in areas outside the mathematics classroom, such as art, science, and everyday life.
Computer with access to Smartboard
Copies of “Rotational Symmetry in the Alphabet” and “Rotational Symmetry in Road Signs” Handouts
Rotation of Shapes Handout
These activities are designed to introduce students to Rotational symmetry. Upon completion of these activities, students will know that an image is said to have rotational symmetry if it looks exactly the same when rotated. To illustrate examples of Rotational Symmetry, I will be using the SmartBoards application for Rotation sent to me by Mrs. Carla Harrington. Using this interactive tool, an image may be selected. After covering with virtual “tracing paper” the image is outlined. Then, you may click on Rotate to see how the “traced image” would appear if the original was rotated at 90°, 180°, 270° and 360°. It can be found at the following website:
1. Give out the sheets titled “Rotational Symmetry in the Alphabet” and “Rotational Symmetry in Road Signs”
2. Have students tell below each letter/sign if it has rotational symmetry.
3. If a letter/sign does have rotational symmetry, have the students to mark the centre of rotation
4. Once students have completed the sheets, discuss the results with the class.
5. Assign Rotation of Shapes Handout for Homework.
Attachment: Worksheet/Activity Student Page