Theorem which can be used to show the triangles ABD and CDB congruent is SSS which is option A .
What is congruent triangles?
Two triangles are said to be congruent if two sides one angle, two angles one side or all the angles of triangles are equal to sides or angles of other triangle.
How to find congruent triangle?
We have been given that AD and BC are equal to each other, AB and DC are equal to each other and we have to congruent the triangles ABD and CDB.
In triangle ABD and CDB
AB=DC (given) (sides)
AD=BC (given) (sides)
BD is common side.
So Triangle ABD and CDB are congruent from SSS because we have taken sides into consideration in all three situations.
Hence SSS is used to congruent the triangles ABD and CDB.
Learn more about congruent triangles at https://brainly.com/question/2938476
#SPJ2
