Congruent and Non-Congruent Figures

What are Congruent Figures?

Congruent shapes are the same shape and size, but we are allowed to flip, slide or turn them.

The pairs of figures in the picture are all congruent.

  • Angles are congruent when they are the same size (in degrees).

  • Sides and line segments are congruent when they are the same length.

We use this symbol to show that two things are congruent:

Ex. A ≅ A

When are Two Figures NOT Congruent?

Whenever you change the area, shape, or dimensions of a figure (i.e., you resize or stretch them in any way), the resulting shape is NON-congruent.

  • Line segments and sides are not congruent if they are not the same length

  • Angles are not congruent if their degree measurements are different (how wide or narrow the separation between their sides are). Because the sides of angles are rays and go on forever, it doesn't matter how long you draw them, they will still be congruent. Only the degree measurements determine whether or not they are non-congruent

The figures on the right are not congruent.

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