Answer:
(8,9)
Explanation:
Given



Required
Determine the 4th point
The coordinate point of a horizontal or a vertical rectangle is given as:
(x1,y1), (x2,y2), (x3,y3), (x4,y4)
Where:

So, we have:
---

----

----

Using the above equations:


Hence, the coordinate of the 4th point is:
