Question

Give the equation of the circle that is tangent to the Y-axis and center is (-3,2)

Answer 1

check the picture below.

since the circle is tangent to the y-axis, namely just touching it, it's radius is, well, you can see it right there in the picture.


`\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{3}{ r} \\\\\\\ [x-(-3)]^2+[y-2]^2=3^2\implies (x+3)^2+(y-2)^2=9`