Identify congruent and similar figures
Key Notes :
🎇Congruent :
✨Two shapes are described as congruent if they are identical.
- The lengths of sides (edges) and sizes of angles must be equal between the two shapes for them to be congruent.
- Reflections or rotations change the orientation of a shape but they are still congruent to the original shape.
- A great way to check if two shapes are congruent is to place one on top of the other. If they match, with no overlaps, they are congruent
Similar :
🎇Two shapes are described as similar if one is an enlargement of the other. The shapes do not need to be orientated the same way.
- The sizes of angles must be equal between the two shapes.
- The shapes must also be proportionally the same. If one side on the enlarged shape doubles in length, all sides must be double the original size shape. The increase in size from one shape to another is called a scale factor.
- The shapes may need to be rotated to find out if they are similar.
🎁It is possible to calculate missing lengths on similar shapes when given either the scale factor or enough information to calculate i
Learn with an example
👉 How are these figures related?
- congruent
- similar but not congruent
- neither similar nor congruent
- Look at these figures:
- They are not the same shape. They are neither similar nor congruent.
👉 How are these figures related?
- congruent
- similar but not congruent
- neither similar nor congruent
- Look at these figures:
- They are the same shape, but they are not the same size. They are similar but not congruent.
👉How are these figures related?
- congruent
- similar but not congruent
- neither similar nor congruent
- Look at these figures:
- They are not the same shape. They are neither similar nor congruent.
Let’s practice!🖊️
