Euclid's Elements Book I, Proposition 4: SAS

If two triangles have two sides equal to two sides respectively, and have the angles contained by the equal sides also equal, then the two triangles are congruent
Click the figure bellow to see the illustration.



Read more at:
Euclid's Elements Book I, Proposition 4

Elearn Geometry Problem 241: Triangle with Equilateral triangles, Congruence

See complete Problem 241 at:
gogeometry.com/problem/p241_triangle_equilateral_congruence_sas.htm

Level: High School, SAT Prep, College geometry

Post your solutions or ideas in the comments.

Congruent Triangles: SAS, SSS, ASA

Congruent Triangles: SAS, SSS, ASA
Demonstrates with animation the various relationships of angles and sides to congruency in triangles.


See animation at:
www.gogeometry.com/geometry/congruent_triangle_journey_1977.htm