Given equation of planes in vector form are r⋅(i+2j−2k)+5=0 and r⋅(2i+4j−4k)−16=0 Equation of planes in cartesian form are x+2y−2z+5=0.....(i) and 2x+4y−4z−16=0 or x+2y−2z−8=0....(ii) We observe that both planes are parallel to each other. ∴ Required distance =