Skip to main content
Search IntMath

What is Congruence in Geometry? 

Understanding the concept of congruence in geometry is essential for any student looking to succeed in math. Congruence is a term used to describe when two shapes have all of the same sides and angles, meaning they are identical. This can be confusing since it often seems like shapes with different sizes can still be congruent. To better understand congruence, let’s look at how it relates to other concepts in geometry. 

Congruent vs Similar Shapes 

It’s important to understand the difference between congruent and similar shapes. Similar shapes are ones that have the same shape but not necessarily the same size or angle measurements. Two circles may both look like circles, but unless they are exactly the same size and their angles measure out identically then they are just similar, not congruent. Congruence applies to all types of polygons (shapes with three or more sides) as well as circles and other curved lines, so long as all of their sides and angles match up exactly. 

Congruence Transformations 

One way that students learn about congruence is by studying transformations, which involve translating (moving or sliding), rotating (turning), or reflecting (flipping) a shape on a coordinate plane without changing its shape or size. By learning about these types of transformations, students can apply them when trying to determine whether two figures are congruent or not. For example, if two figures have been rotated 90 degrees but are otherwise identical then they would still be considered congruent even though their orientation has changed due to the rotation transformation. 


Overall, understanding what is congruence in geometry is critical for anyone looking to do well in math classes involving geometry. Knowing that two figures can be considered congruent even if one is rotated or reflected helps students better apply this concept when doing math problems involving shapes and angles. With practice and patience, students should be able to master the concept of congruence fairly quickly!

Tips, tricks, lessons, and tutoring to help reduce test anxiety and move to the top of the class.