12x12 or 9x12 be big enough for max 75 guests?

We are going to reserve a 20x20 frame tent and pricing dance floors. A 12x12 is 363.00 and 9x12 is 345.00. We are going to have 75 guests or less for the reception and tables will be very few and not under the tent. Only the DJ will need to be under the tent with he dance floor. Is this big enough?