Establish Triangle Congruence with Three Sides
Matching all three corresponding side lengths establishes triangle congruence through SSS.
About 20 minutes, plus any extended practice
Open lesson 1Geometry: Congruence and Bisector Reasoning
Congruence fixes a figure’s shape and size, while correspondence identifies matching vertices and sides. Perpendicular and angle bisectors encode equidistance or equal-angle properties that can be used and checked in a construction.
Before you begin
- Read named triangle vertices; know perpendicular lines and equal angle measures.
Choose by skill rather than age alone. Read with an adult when useful, revisit a lesson, or explore another grade.
Follow the lesson sequence
Read the Vertex Order in a Congruence Statement
The written order in triangle ABC congruent to DEF pairs A with D, B with E, and C with F.
About 20 minutes, plus any extended practice
Open lesson 2Use Equidistance from a Segment’s Endpoints
A segment’s perpendicular bisector crosses its midpoint at a right angle.
About 20 minutes, plus any extended practice
Open lesson 3Check Equal Angles in a Bisector Construction
An angle bisector divides an angle into two congruent angles.
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
- California CCSS mathematics topic reference: topic reference — Geometry: Congruence and Bisector Reasoning
These references informed the topic selection. They do not certify complete standards alignment.