Consider a rhombus PQRS such that ∠PRQ = 30º. If the diagonals of the rhombus intersect at point O, then what is the measure of ∠PSQ?

Given that PQRS is a rhombus and ∠PRQ = 30º.
⇒ ∠ORQ = 30º

Since PS ∥ RQ and PR act as a transversal, therefore,
∠SPR = ∠PRQ = 30º  (Alternate interior angles)
Now,
∠POS = 90º (∵ Diagonals of a rhombus bisect each other at right angles)
Applying angle sum property in △POS,
∠SPO+∠POS+∠PSO=180°

⇒30°+90°+∠PSO=180°

⇒∠PSO=60°
Again, ∠PSO=∠PSQ=60°

⇒∠PSQ=60°