Question 986926
The midpoint is the average of the x and y values of the endpoints.
{{{x[m]=(3+x)/2=3}}}
{{{3+x=6}}}
{{{x=3}}}
.
.
{{{y[m]=(y-9)/2=4}}}
{{{y-9=8}}}
{{{y=17}}}
.
.
.
*[illustration fd18.JPG].