Which two figures are called equal?

Equal are such figures that can be combined using any type of movement (central and axial symmetry, rotation and parallel translation).

In such figures, all sides and angles are respectively equal.

For example, if triangles ABC and A₁B₁C₁ are given, then they are equal if the sides (AB = A₁B₁, BC = B₁C₁, AC = A₁C₁) and angles (angle A = angle A₁, angle B = angle B₁, angle C = angle C₁).

Also, in equal figures, the corresponding points and lines are equal. For example, in the same equal triangles ABC and A₁B₁C₁ the bisectors, medians, heights, radii of the inscribed and circumscribed circles, centroids, etc. will be equal.