Question

The radius of the circle in which the sphere x2 + y2 + z2 + 2x – 2y – 4z – 19 = 0 is cut by the plane x + 2y + 2z + 7 = 0 is
(a) 2

(b) 3

(c) 4

(d) 1.

Answer 1

(b) : The radius and centre of sphere
x2 + y2 + z2 + 2x – 2y – 4z – 19 = 0 is