Congruent Shapes
Congruent shapes are basically identical twins in the world of maths - they're exactly the same shape and size as each other. Think of it like having two identical phone cases: one might be rotated or flipped over, but they're still exactly the same size and shape.
The key thing to remember is that congruent shapes can be rotated, reflected (flipped), or moved around, but they can never be made larger or smaller. If someone stretches or shrinks a shape, it's no longer congruent - it becomes what we call a similar shape instead.
You can spot congruent shapes by checking if all their corresponding angles are equal and all their corresponding sides are the same length. This is dead useful for solving geometry problems and understanding transformations.
Quick Tip: If you can place one shape perfectly over another (even after rotating or flipping), they're congruent!
When you're working with transformations, three of them keep shapes congruent: reflection (flipping), rotation (turning), and translation (sliding). However, enlargement always changes the size, so it creates similar shapes rather than congruent ones.