I will just give an outline of how to prove it. You can write it up in a two-column proof. A rhombus is a parallelogram with four congruent sides. So, all sides of rhombus ABCD are congruent. That is AB ≅ BC ≅ CD ≅ ADWe also know that the diagonals of a parallelogram bisect each other. Since a rhombus is a parallelogram, it also has this property. Therefore BE ≅ DE, AE ≅ CE. Therefore all 4 triangles are congruent by SSS. Edwin