Question

M (3,4) is the midpoint of line JK, where J has coordinates (1,2). find coordinates of K

Answer 1

let (xK,yK) be the coordinate of K
as M is the midpoint of line JK -> (xK+xJ)/2 = xJK
(xK+1) / 2 = 3
xK + 1 = 6 -> xK= 5

and (yK + yJ)/2 = yJK
(yK + 2 )/2 = 4
yK + 2 = 8 -> yK =6

so coordinate of K = (5,6)