I suppose that if the sub-species of social dancers and all those low grade competitors were being told such rubbish, they would be well served by asking around to see if anyone could introduce them to a decent teacher.
Most people are familiar with diagrams showing "Directions of Steps or Positions of Body in Relation to the Room" (Alex Moore's coming immediately to mind). We have the right hand side of the diagram helpfully marked "Side of Room", and the Centre is to the left. LOD is up and against LOD is down. We have the eight directions we all know, and can see how to interpret the alignment instructions given in the technique books. However, as the social dancers and low grade competitors presumably couldn't be expected to own technique books, we hope that their teachers will explain in terms that their limited capacity for dancing can comprehend.
Now, we have your diagram. Centre is centre, and we have but two lines, both extending from the centre of the paper to the top corners. But the paper isn't square: it's A4, so the angles are not right - never mind. By careful deduction, we spot that the line leading to the top right corner must be diag to wall, but of course, we find that the other is the exact OPPOSITE of diag to wall against LOD - for it is diag to centre.
Back to those lines: three quarters of the way from the centre point to the corners we mark the two lines (label them: "Toes here, stupid") and measure the distance between the points: 6 1/4 inches, give or take). Hmm.
Now I take my partner onto the dance floor, and facing DC, I dance an open telemark. Our feet didn't end up where the diagram said. Where did I go wrong? I think I'll just stick to social dancing, thanks.