Okay. So first I divided 70 by 12 giving me an answer of 5.833333, rounding it to 5.8. Meaning 5 chairs per table (considering you can't have 0.8 of a chair).
5 chairs for each table, 10 for two tables, and so on. So, yeah, I could be wrong, and if so I'm sorry.
Both a rhombus and a rectangle have diagonals that are perpendicular bisectors, but the ones formed in a square are all congruent, so that is probably the most descriptive one.
