More Lessons for Grade 9

Math Worksheets

Videos, worksheets, solutions and activities to help Geometry students learn about figures that are congruent.

Congruent Figures Part 1 -

Identify Corresponding Part and Congruent Triangles 4.1

This video is about congruent polygons.

Congruent polygons have congruent corresponding parts, meaning the corresponding angles are congruent and the corresponding sides are congruent.

It is important, when naming congruent polygons, to keep the corresponding vertices in order.

Proving Triangles Congruent - Definition of Congruent Triangles

The second part of this series about congruent figures is proving triangles congruent.

At this point, there is only one way to prove triangles congruent, with the definition of congruent triangles. Congruent triangles have 3 pairs of corresponding angles and 3 pairs of congruent angles. So, to prove two triangles congruent, we must establish that all 3 pairs of corresponding sides and angles are congruent.

The third angle theorem states, if two angles of one triangle are congruent to two angles of another triangle, the third angles are congruent to each other.

Proving Triangles Congruent - Definition of Congruent Triangles 4.1

The third part of this series about congruent figures is proving triangles congruent.

At this point, there is only one way to prove triangles congruent, with the definition of congruent triangles. Congruent triangles have 3 pairs of corresponding angles and 3 pairs of congruent angles. So, to prove two triangles congruent, we must establish that all 3 pairs of corresponding sides and angles are congruent.

Rotate to landscape screen format on a mobile phone or small tablet to use the **Mathway** widget, a free math problem solver that **answers your questions with step-by-step explanations**.

You can use the free Mathway widget below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.