The form of the equation of the circle is
[tex](x-h)^2+(y-k)^2=r^2[/tex]Where (h, k) are the coordinates of the center
r is the radius
Since the endpoints of the diameter are (11, 2) and (-7, -4), then
The center of the circle is the midpoint of the diameter
[tex]\begin{gathered} M=(\frac{11+(-7)}{2},\frac{2+(-4)}{2}) \\ M=(\frac{4}{2},\frac{-2}{2}) \\ M=(2,-1) \end{gathered}[/tex]The center of the circle is (2, -1), then
h = 2 and k = -1
Now we need to find the length of the radius, then
We will use the rule of the distance between the center (2, -1) and one of the endpoints of the diameter we will take (11, 2)
[tex]\begin{gathered} r=\sqrt[]{(11-2)^2+(2--1)^2} \\ r=\sqrt[]{9^2+3}^2 \\ r=\sqrt[]{81+9} \\ r=\sqrt[]{90} \\ r^2=90 \end{gathered}[/tex]Now substitute them in the rule above
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