*Kiddle Encyclopedia.*

# Congruence (geometry) facts for kids

In geometry, two figures or objects are congruent if they have the same shape and size. Also if one has the same shape and size as the mirror image of the other.

More formally, two sets of points are called **congruent** if, and only if, one can be transformed into the other by isometry. For isometry, *rigid motions* are used.

This means that one object can be repositioned and reflected (but not resized) so it coincides exactly with the other object. So two distinct plane figures on a piece of paper are congruent if we can cut them out and then match them up completely. Turning the paper over is permitted.

Congruent polygons are polygons that if you fold a regular polygon in half that is a congruent polygon.

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Congruence (geometry) Facts for Kids.