Common Core: High School - Geometry

Explore the principles and applications of geometry, including shapes, theorems, and real-world problem-solving.

Advanced Topics

Congruence and Similarity

Comparing Shapes

Shapes can be congruent (exactly the same size and shape) or similar (same shape but different sizes).

Congruence

Two shapes are congruent if they can be matched exactly using rotations, reflections, or translations. Their corresponding sides and angles are identical.

Similarity

Shapes are similar if their angles are equal and their sides are proportional. This concept helps us create scale models and maps.

Proving Congruence and Similarity

We use criteria like SSS (Side-Side-Side), SAS (Side-Angle-Side), and AA (Angle-Angle) to prove if triangles are congruent or similar.

Real-World Relevance

Engineers use these concepts to create models and blueprints, ensuring everything fits together perfectly!

Key Formula

\[\frac{a_1}{a_2} = \frac{b_1}{b_2} = \frac{c_1}{c_2}\]

Examples

  • Designing a scaled-down model of a building.

  • Ensuring puzzle pieces fit together perfectly.

In a Nutshell

Congruence means exact match; similarity means same shape, different size.

Key Terms

Congruent
Shapes that are exactly the same in size and shape.
Similar
Shapes with the same shape but different sizes.