Yes I know but remember this was a tetrahedral which has a angle of 109.5 and a lone pair which reduces it by 2-2.50 and that's how I came to 107.5. I'm not saying I'm correct, that's just what I thought so I could be wrong.
I don't think so because a square planar has 1 lone pair and a single electron so the single electron goes at the top and pair of electrons at the bottoms which pushes the 4 bonds between them, 2 on each side. I was thinking about that but I didnt remember the angle for it so I went for the 107.5