midpoint of (x1,y1) and (x2,y2) is [tex](\frac{x_1+x_2}{2}, \frac{y_1+y_2}{2}[/tex]
so if midpoint is (-3,2) and one point is (0,11) then
[tex](-3,2)=(\frac{0+x_2}{2}, \frac{11+y_2}{2})[/tex]
[tex]-3=\frac{x_2}{2}[/tex]
[tex]-6=x_2[/tex]
[tex]2=\frac{11+y_2}{2}[/tex]
[tex]4=11+y_2[/tex]
[tex]-7=y_2[/tex]
the coordinates of k is (-6,-7)
circumference=2*pi*r
area=pi*r^2
if r=3 then
circumference=2*pi*3=6pi in
area=pi*3^2=pi*3*3=9pi in²
