Khan Academy (English - US curriculum)
Math by grade
High school
High school geometry
Congruence
Working with triangles
Working with triangles
Learn how to solve different geometric problems using triangle congruence.
Corresponding angles in congruent triangles
Find angles in congruent triangles
Isosceles & equilateral triangles problems
Find angles in isosceles triangles
Finding angles in isosceles triangles
Finding angles in isosceles triangles (example 2)