Geometry

Question Analysis:
This question involves applying the mid - point formula to find the mid - point of a diagonal of a quadrilateral.
The main focus is accurately using the coordinates of the endpoints of the diagonal in the mid - point formula.

Key Concept Explanation:
The mid - point formula for two points and is .
It gives the central point between two given points in the coordinate plane.

Step - by - Step Solution:
1. Identify the coordinates of points and :
   - For point , , . For point