Question

a circle is shown on the coordinate plane below. what is the equation of this circle

Answer 1

What is the equation of this circle?

(x + 1)2 + y2 = 2

(x – 1)2 + y2 = 4

(x + 1)2 + y2 = 4

(x – 1)2 + y2 = 2

Answer 2

equation of circle is given by formula: \[\left( x-h \right)^{2} + \left( y-h \right)^{2} = r ^{2}\]
where (h,k) is the center and r is the radius.
in your case the center is (-1,0) and r is \[\left| 1--3 \right|\]
substitute in \[\left( x-h \right)^{2} + \left( y-h \right)^{2} = r ^{2}\]
it becomes \[\left( x--1 \right)^{2} + \left( y-0 \right)^{2} = 2^{2}\]
now simplify

Answer 3

note the \[\left| 1--3 \right|\] is the diameter not radius