If both pairs of opposite sides of quadrilateral ABCD are congruent, prove that △ABC is congruent to △CDA

Question

The picture is a quadrilateral with point A on the bottom left corner, point B on the bottom right corner, point D on the top left corner, point C on the top right corner, with a diagonal line from A to C

Answer 1

The triangles are congruent because all three sides are congruent.  (SSS)

 

AB is congruent to CD

AD is congruent to BC

AC is congruent to AC