Adjacent angles of a parallelogram are supplementary.

In parallelogram RISK, ∠RKS + ∠ISK = 180°

120° + ∠ISK = 180°

∠ISK = 60°

Also, opposite angles of a parallelogram are equal.

In parallelogram CLUE, ∠ULC = ∠CEU = 70°

The sum of the measures of all the interior angles of a triangle is 180º.

x + 60° + 70° = 180°

x = 50°