Question

the figure shows quadrilateral abcd. the two diagonals of abcd, bd and ac, are perpendicular to one another, and bc ≅ dc. which theorem of triangle congruency can be used to prove that △bec≅△dec? angle - side - angle side - angle - side hypotenuse - leg side - side - side

Explanation:

We know that $BC = DC$ (given), $\angle BEC=\angle DEC = 90^{\circ}$ (diagonals are perpendicular) and $EC$ is common to both $\triangle BEC$ and $\triangle DEC$. So, we have two - sides and the included right - angle equal. The Side - Angle - Side (SAS) congruence theorem states that if two sides and the included angle of one triangle are congruent to two sides and the included angle of another triangle, then the two triangles are congruent.

Answer:

Side - Angle - Side