Identify Parallel and Perpendicular Lines
Read the supplied intersection or direction description.
About 20 minutes, plus any extended practice
Open lesson 1Classify Lines and Figures with Symmetry
Use parallel/perpendicular lines, angle categories, shape attributes, and reflection symmetry.
Before you begin
- Identify polygons; measure acute, right, and obtuse angles.
Choose by skill rather than age alone. Read with an adult when useful, revisit a lesson, or explore another grade.
Follow the lesson sequence
Classify a Triangle by Its Angles
Read the supplied angle measures of a valid triangle.
About 20 minutes, plus any extended practice
Open lesson 2Use Parallel Sides and Right Angles to Classify
Read only the stated attributes and determine the most specific category justified by them.
About 20 minutes, plus any extended practice
Open lesson 3Test Reflection Symmetry with a Fold
Use the supplied figure and proposed fold.
About 20 minutes, plus any extended practice
Open lesson 4Review and transfer
After the lessons, try 4 new review cases and a practical task. Each answer has an explanation and a link back to the related lesson.
Open the unit reviewGuest answers are temporary. Keep your own paper or document; this unit does not certify completion or record a school grade.
Topic references
- Common Core State Standards, mathematics: 4.G.A.1 — Use parallel/perpendicular lines, angle categories, shape attributes, and reflection symmetry.
- Common Core State Standards, mathematics: 4.G.A.2 — Use parallel/perpendicular lines, angle categories, shape attributes, and reflection symmetry.
- Common Core State Standards, mathematics: 4.G.A.3 — Use parallel/perpendicular lines, angle categories, shape attributes, and reflection symmetry.
These references informed the topic selection. They do not certify complete standards alignment.