Which attribute is not always true for a rhombus?
a) four equal sides
b) four right angles
c) opposite congruent angles
d) two sets of parallel sides

B) four right angles

Step-by-step explanation:

The definition of a rhombus is that it is an equilateral quadrilateral.

This definition knocks out A.

C and D can also be knocked out because opposite angles are congruent, so they both must also be true.

Also, B is the requirement for a square, not a rhombus.

astronomers is your final answer! : )