Question

How do you round 2.8497 × 10^3 and 349.69 to 3 significant figures?

When I have inserted [what I thought was the correct answers] ie; 350.0 and 2.85, I was told it was incorrect.

Answer 1

Your answer for rounding 2.8497 x 10^3 is correct: 2.85 x 10^3.

350.0 is not correct because it has 4 sig figs. The proper rounding would be simply 350. with not additional zeros.