Congruence

From Simple English Wikipedia, the free encyclopedia

An example of congruence. The two shapes on the left are congruent. The third is similar to the first two, but not congruent. The last shape is neither similar nor congruent.

Numbers are equal, geometrical objects are congruent. Two shapes are congruent if one can be moved or rotated so that it fits exactly where the other one is. If you have to shrink or enlarge one of the two objects, they are not congruent. They are called similar.

Examples:

• all squares that have the same length of their sides are congruent.
• all equilateral triangles that have the same length of their sides are congruent.