Question

Which is a counterexample to the following faulty definition? "A square is a figure with four congruent sides."

A Quadrilaterals have four sides.
B A rectangle has four right angles.
C A rhombus has four congruent sides.
D Equilateral triangles have congruent sides.

Answer 1

The correct answer of the given question above would be option D. The counterexample to the following faulty definition  "A square is a figure with four congruent sides." is that: Equilateral triangles have congruent sides. Hope this is the answer that you are looking for. 

Answer 2

A rhombus has four congruent sides.