Area is 28 for number 33.
7*8=56
56/2=28
If you were to make your own measurements, your significant digits should include all of the measurable digits (the digits that correspond to the marks on the ruler) as well as one estimated position beyond the smallest measureable digit (the 5 in 3.5 cm, and the 2 in 3.52 cm).
I would choose A
You can simply try every answer and see which one gives you 16a-24ab
