Geometry

Question Analysis:
This question checks when a parallelogram becomes a square using diagonal properties and algebra.
The main focus is on combining perpendicularity and equal length of diagonals.

Key Concept Explanation:
A parallelogram becomes a square if:
All sides are equal (implied if diagonals are perpendicular), and
Diagonals are congruent (must be verified with an equation).

Step-by-Step Solution:
Set the diagonal expressions equal:
x + 6 = 2x - 4<...