Geometry

Question Analysis:
Applies midpoint congruence to find missing vertex coordinates.

Key Concept Explanation:
In parallelograms, the midpoints of both diagonals must coincide.

Step-by-Step Solution:
Calculate EG midpoint:
((1 + 5)/2, (1 + (-1))/2) = (3, 0)
Let H = (x, y). FH midpoint must be (3, 0):
((4 + x)/2, (2 + y)/2) = (3, 0)
Solve:
(4 + x)/2 = 3 → x = 2
(2 + y)/2 = 0 → y = -2

Common Mist...