Question

The coordinates of point T are (0,5). The midpoint of ST is (2, -8). Find the coordinates of point S.

Answer 1

(4, -21)

Explanation:

The midpoint of two points S and T will be (average x, average y).

Let's denote the x value of S to be Sx, and the same for Tx, Sy, and Ty.

The midpoint is given by ((Sx+Tx) / 2, (Sy+Ty)/2), so let's solve for each coordinate of S using the fact we know the midpoint is (2,-8) and T = (Tx, Ty) = (0,5).

(Sx + Tx) / 2 = 2

Sx + Tx = 4

Sx = 4 - Tx = 4 - 0 = 4

(Sy + Ty) / 2 = -8

Sy + Ty = -16

Sy = -16 - Ty = -16 - 5 = -21

So S = (4, -21)

Answer 2

I think it’s (4, -21)