Final answer:
A diagonal of a rhombus bisects it into two congruent triangles.
Step-by-step explanation:
A rhombus is a quadrilateral with all sides congruent. If we draw the diagonal of a rhombus, it will create two congruent triangles. This is because the diagonals of a rhombus bisect each other, meaning they divide each other into two equal parts. By the definition of a rhombus, all sides are congruent. By the reflexive property of congruence, the two sides of each triangle that share the diagonal are congruent. So, by the corresponding parts of congruent triangles are congruent (CPCTC), the other corresponding sides and angles of the triangles are congruent. Finally, by the definition of a segment bisector, the diagonal bisects the rhombus and divides it into two congruent triangles.