Question

The midpoint QR is M (-1,2). One endpoint is R (3,4). Find the coordinates of the other endpoint.

Answer 1

M = (x₁ + x₂)/2  , (y₁ + y₂)/2

(-1, 2) = $\frac{3 + x}{2} , \frac{4 + x}{2}$

At this point, it is easier to separate the x's and y's into two different equations:

x's: -1 = $\frac{3 + x}{2}$

     -2 = 3 + x

     -5 = x

y's: 2 = $\frac{4 + x}{2}$

     4 = 4 + x

     0 = x

Answer: (-5, 0)