I don't think the answer is 36pi it is only the centre. To find the area , we have to determine the radius, which according to the Q stem can be derived from the two points at which the circle intersects at x axis, say (x,0) and (-x,0). The distance given between the two points is 16,
sqrt((2x)^2)=16 ===>x=2 or -2
Therefore, the two points are (2,0) and (-2,0). The radius will be then distance between (0,6)and (2,0)
or (0,6) and (-2,0) which gives sqrt(40). The area will then be 40pi.
But I am not sure whether this is the correct answer or the way to derive it. Need confirmation. Thanks.