Answer: 
Co-ordinates of point R is (26,2) 
Step-by-step explanation: 
Given point: 
Endpoint S(8,4) 
Mid-point M of segment RS (17,3) 
Let endpoint 
 have co-ordinates
 have co-ordinates 
 
 
Using midpoint formula: 
 
 
Where 
 and
 and 
 are co-ordinates of the endpoint of the segment.
 are co-ordinates of the endpoint of the segment. 
Plugging in values to find the midpoint of segment KN. 
 
 
We know 
 
 
So, we have 
 
 
Solving for 
 
 
 
 
Multiplying both sides by 2. 
 
 
 
 
Subtracting both sides by 8. 
 
 
∴ 
 
 
Solving for 
 
 
 
 
Multiplying both sides by 2. 
 
 
 
 
Subtracting both sides by 4. 
 
 
∴ 
 
 
Thus co-ordinates of point R is (26,2) (Answer)