Question

Find the coordinates of Q, the other endpoint of the line segment , given P (8, 2) and M (2, 5), the midpoint.

Answer 1

From P to M the change on the x axis is 8-2 = 6 units
on the y axis 5-2 = 3 units
The change on the x axis is negative, on the y axis it is positive.

Now as M is the midpoint the change from P to M is the same as the change from M to Q.

Thus M (2-6, 5+3) = (-4, 8)