Lesson 7

Symmetry

Est. Class Sessions: 1
X

Mathematical Standards

4.G.A
Draw and identify lines and angles, and classify shapes by properties of their lines and angles. (4.G.A.2, 4.G.A.3)

Standards for Mathematical Practice

MP1.
Make sense of problems and persevere in solving them.
MP2.
Reason abstractly and quantitatively.
MP3.
Construct viable arguments and critique the reasoning of others.

Students explore line (reflective) and turn (rotational) symmetry of polygons.

Content in this Lesson

  • Identifying line (reflective) symmetry [E7].
  • Identifying turn (rotational) symmetry [E9].
  • Classifying shapes by number of lines of symmetry [E6].

Daily Practice and Problems S–T

S. Estimating Angles

T. Angles

X

Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Books

Student Guide
Student Activity Book

Teacher Resources

Teacher Guide - digital

Supplies for Students

scissors
tape
blank sheet of paper
ruler or straight edge
construction paper
one set of Power Polygons™ (Shapes A–O)

Materials for the Teacher

Professor Peabody's Snowflake Master (Teacher Guide), optional
Geometry Word Chart from previous lessons
Unit 9 Assessment Record
one set of Power Polygons™ (Shapes A–O)
scissors images of snowflakes chart paper

Materials Preparation

Snowflakes. Find images of snowflakes to share with the class. Some of the best are photographs by Wilson A. Bentley of Jericho, Vermont. During his life he photographed thousands of snowflakes and published a book, Snow Crystals, and numerous articles on the subject. Some images are in the Student Guide.

Prepare Snowflakes. Have a student carefully cut out the snowflake on the Professor Peabody's Snowflake Master keeping the rest of the page intact.

Geometry Word Chart. Prepare sheets of chart paper for the Geometry Word Chart. The class will need two clean sheets during Summarizing the Lesson. Write “Lines of Symmetry” on top of one and “No Lines of Symmetry” on the other.

Assessment in this Lesson

Assessment Expectation Assessed

Finding Symmetry Question 1
Student Activity Book
Page 353

E7.
Identify line (reflective) symmetry.

DPP Item T
Angles
Teacher Guide - digital

E2.
Classify acute, obtuse, and right angles.
E11.
Estimate the size of an angle using 90°, 180°, and 360° as benchmarks.