Practice Test 10

Consider quadrilateral $$WXYZ$$ where the diagonals $$WY$$ and $$XZ$$ intersect at point $$M$$, with $$WM = MY$$ and $$XM = MZ$$. Additionally, $$WY = XZ = 12$$. What can be concluded about quadrilateral $$WXYZ$$?

Using only a compass and straightedge, a student is constructing the perpendicular bisector of $\overline{AB}$. The student has already drawn equal-radius arcs centered at $A$ and $B$ intersecting at $P$ and $Q$, and then drew line $\overleftrightarrow{PQ}$. Which step is unnecessary for this construction?