An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) Agreeing; accordant.
2) Math.: → congruent number.
3) Geometry: → congruent angles, → congruent circles, → congruent line segments, → congruent polygons, → congruent triangles.

Congruent "suitable, proper," from L. congruentem (nominative congruens) "agreeing, fit, suitable," p.p. of congruere, literally "to come together, agree, correspond with," from → com- "with" + a lost verb *gruere, *ruere "fall, rush."

Damsâz "agreeing, consenting, harmonious," maybe from hamsâz "unanimous," → compatible.

Two angles if they have the same measure. Congruent angles may lie in different orientations or positions.

→ congruent; → angle.

Two circles if they have the same size.

→ congruent; → circle.

Two line segments if they have the same length. They need not lie at the same angle or position on the plane.

→ congruent; → line; → segment.

Number theory: An → integer N if there exists a → right triangle with → rational sides so that the area of the triangle is N. For example, the number N = 6, because of the 3-4-5 triangle.

→ congruent; → number.

Polygons that have an equal number of sides, and all the corresponding sides and angles are congruent. However, they can be in a different location, rotated or flipped over.

→ congruent; → polygon.

Two triangles when all corresponding sides and interior angles have the same measure. The triangles will have the same shape and size, but one may be a mirror image of the other.

→ congruent; → triangle.