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Both shapes have exactly 4 sides with equal lengths.
If two shapes are congruent it means that they are exactly the same, same side lengths and angle measures.
parallelograms
Lenses have different focal lengths due to their varying shapes and materials. A thicker lens will have a shorter focal length, while a thinner lens will have a longer focal length. Additionally, the refractive index of the lens material will affect its focal length.
Segments of equal length are congruent segments. Shapes can also be congruent if their side lengths and angle measures are equal with each other.
If you mean 'Irregular' and 'Regular shapes' then this is the answer. A regular shape is a shape that has E.g. 4 sides that are the same length but and irregular shape is one that has the same amount of sides, just different lengths.
Regular shapes have equal side lengths and equal angles
An infinite number. A polygon with any number of sides can be equilateral (ie have sides of equal length).
When two shapes have proportionally equivalent lengths and angles, they are geometrically similar. For example, take a triangle with sides of length 3, 4, and 5. Another triangle with side lengths 6, 8, and 10 would be geometrically similar to it because its angles are the same and its side lengths are proportional.
2d shapes only have length and width, while 3d shapes have length, width and depth.