Shapes with identical shapes and sizes are called congruent. They can also be mapped onto each other using translation, rotations and reflections.
Triangles which are congruent satisfy the following rules:
1. Three sides of one triangle are equal to the three sides of the other triangle
2. Two sides and the included angle in one triangle are equal to two sides and the included angle in the other.
3. Two angles and one side of one triangle are equal to the corresponding two angles and side in the other.
4. The hypotenuse and one side of the right-angled triangle is equal to the hypotenuse and one side of another right-angled triangle.