Use a projector do you have one?
12 to 16 should be the only one.
i looked over ti and 9/12 is also equivalent.
if you multiple by 1.5 that gets you 9/12
Answer:
1. Formula: b * h ÷ 2
12 * 3 = 36 ÷ 2 = 18 in^2
2. Formula: b * h ÷ 2
5 * 8 = 40 ÷ 2 = 20 ft^2
I could only help on two. Hope it helps though! =)