Learning Goal
Prove theorems about lines
Teacher tools for this standard
Lesson Plan · Guided Notes · Exit Ticket · Re-teach · Homework
Teacher tools for this standard
Lesson Plan · Guided Notes · Exit Ticket · Re-teach · Homework
- Lesson Plan →Objectives, pacing and practice, built from this lesson's brief.
- Guided Notes →One page your students fill in and keep.
- Exit Ticket →Three items at the end of class. No student accounts.
- Re-teach →After an exit ticket: who missed what, and what to do tomorrow.
- Homework →Assign practice; it grades itself.
**HSG.CO.C.9**: Prove theorems about lines and angles. Theorems include: vertical angles are congruent; when a transversal crosses parallel lines, alternate interior angles are congruent and corresponding angles are congruent; points on a perpendicular bisector of a line segment are exactly those equidistant from the segment's endpoints.
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HSG.CO.C.9: Prove theorems about lines and angles. Theorems include: vertical angles are congruent; when a transversal crosses parallel lines, alternate interior angles are congruent and corresponding angles are congruent; points on a perpendicular bisector of a line segment are exactly those equidistant from the segment's endpoints.
What you'll learn
- Prove that vertical angles are congruent using the properties of linear pairs and supplementary angles
- Prove that when a transversal crosses parallel lines, alternate interior angles are congruent
- Prove that when a transversal crosses parallel lines, corresponding angles are congruent
- Prove the Perpendicular Bisector Theorem: points on a perpendicular bisector of a segment are exactly those equidistant from the segment's endpoints
- Construct logical proofs using both two-column and paragraph formats, citing definitions, postulates, and previously established theorems as justifications
Slides
Step through the lesson, or watch it as a narrated video • 2 slide decks
Angle theorems and proofs
✓ Start herePerpendicular bisector and proof skills
Practice
Try it on your own