Significant figures vary from course to course.. I took general chemistry from a physical chemistry teacher, so we used the significant figures for physics. Regardless, the basic structure is the same.
If you are actually physically measuring something, then you should estimate between the smallest lines. For instance, if you have a ruler that goes up to millimeters, then you should be able to estimate where your line falls in between those lines. Say this gives you a distance of 136.5 mm. The 0.5 is the digit that you are unsure of, but you are sure of the first three. So you have three significant figures.
Based on the measurements you have provided, you will actually have two significant figures (0.7 cm has two). So your answer would be 10 cm2.
I've been dealing mostly with sig figs in physics lately and not so much in chemistry, so I might be wrong. But I hope this at least helps.