geometryendpoints
posted by Jessica K .
Directions in my book say, "find the coordinates of the other ENDPOINT of a segment with the given endpoint and midpoint M."
example: R(2,6)
M(1,1)
I really need help.

I am assuming that (2,6) are the x and y coordinates of point R.
If the coordinates of the midpoint are (1,1), the other endpoint has a decrease in x of 3, and a decrease of y by 5. (The same as from R to M)
That makes the coordinates of the other endpoint (4, 4) 
One way it to subtract the x values 2(1) = 3. Since that is 1/2 the line segment, then 1 3 = 4 for the x value of the end of the other segment. The value of the y segment is done similarly (61 = 5 and 15 = 4 so the coordinates of the other end point is (4,4). You can check these values by plugging the values into y = mx + b to see if all satisfy the equation.

Oh. But I don't quite understand the process.