1. The problem statement, all variables and given/known data The question is as attached in the picture. 3. The attempt at a solution I understand and got the answer to part (a) but from (b) onwards I am completely lost. Here are my assumptions: 1)Edges of 'cube' are still of length a 2)Successive planes are parallel But, there is some things remain unknown: 1)Where is the origin at? The centre of the cube? or at the bottom leftmost point? 2)Why does the plane pass through (a/2, 0, a/2)? 3) Do we assume that the plane contains the origin? Then won't the equation be r . n = 0?