The two figures are congruent if they have exactly the same size and shape. The congruent figures have congruent sides and angles. The congruence between two sides and angles is shown by the symbol 
.
The two triangles ABC and XYZ shown below are congruent because their corresponding sides and angles are congruent.
The table below shows the corresponding sides and corresponding angles that are congruent.
The ratio of lengths of two corresponding sides of congruent figures is always 1. Congruent figures have same area and perimeter. So the ratio of areas and volumes of two congruent figures is also 1.