A circle on the xy-plane has its center at (3, p) and touches the x-axis at exactly one point. If the area of the circle is 4\pi , which of the following could

Question

I don't understand how to do this problem.

Answer 1

area = 3/pi = pir^2

r^2 = 3/pi^2

= radius squared

center is the point (3, (sqr3)/pi)

equation of the circle is of the form (x-h)^2 + (y-k)^2 = r^2

where (h,k) is the center and r= radius

plug in the values

(x-3)^2 + (y- (sqr3)/pi)^2 = 3/pi^2