Question

M(9, 8) is the midpoint of mc136-1.jpg. The coordinates of S are (10, 10). What are the coordinates of R?

Answer 1

well the midpoint formula for x is

\[x_{m} = \frac{x_{s} + x_{r}}{2}\]

so substitute \[x_{m} = 9...and... x_{s} = 10\]

so you get

\[9 = \frac{10 + x_{r}}{2}\]

so to find xr multiply both sides of the equation by 2 and then subtract 10


for y, the formula is

\[y_{m} = \frac{x_{s}+x_{r}}{2}\]

and y_m = 8 and y_s = 10

solve for y_r

hope this helps