## Geometry: Common Core (15th Edition)

$I(5,1)$
Use the midpoint formula to find the x-coordinate of point I. $x_M=\frac{x_G+x_I}{2}$ $2=\frac{-1+x_I}{2}$ multiply each side by 2 $2\times2=\frac{-1+x_I}{2}\times2$ $4=-1+x_I$ add 1 to each side $4+1=-1+x_I+1$ $5=x_I$ Use the midpoint formula to find the y-coordinate of point I. $y_M=\frac{y_G+y_I}{2}$ $-1=\frac{-3+y_I}{2}$ multiply each side by 2 $-1\times2=\frac{-3+y_I}{2}\times2$ $-2=-3+y_I$ add 3 to each side $-2+3=-3+y_I+3$ $1=y_I$