Question

Determine equation of the circle that contains the points (3, 2), (3, -6), (7, -2) and (-1, -2)

Answer 1

Check the picture below.

$\bf \textit{equation of a circle}\\\\ (x- h)^2+(y- k)^2= r^2 \qquad center~~(\stackrel{3}{ h},\stackrel{-2}{ k})\qquad \qquad radius=\stackrel{4}{ r}\\[2em] [x-3]^2+[y-(-2)]^2=4^2\implies (x-3)^2+(y+2)^2=16$