The equation of plane which is passing through the point (1, −2, 1) is given by a(x – 1) + b(y + 2) + c(z – 1) = 0 is perpendicular to the given plane. 2a – 2b + c = 0 a – b + 2c = 0 ⇒ a – b = −2c −4c + c = 0 ⇒ c = 0 Therefore, a = b. Hence, the equation of the required plane is x + y + 1 = 0 Therefore, the distance of point (1, 2, 2) is