Which mass measurement contains four significant figures? (1) 0.086g (3) 1003g(2) 0.431g (4) 3870g

option (3) 1003 g.

Explanation:

1) 0.086 g has two signficant figures, because the zeros to the left of the decimal period and to the right of the decimal period and before the first non zero digit do not count. Those zeros only tell the place value of the other digits. So, only 8 and 6 are significan figures: two.

2) 0.431g has three significant figures: the 0 before the decimal period do not count. Only 4, 3, and 1 are signficant figures: three.

3) 1003 g has four significant figures, because the zeros in between the other digits count. So, 1, 0, 0, and 3 are significant figures.

4) 3870 g has three significant figures, because the 0 after the other 3 digits is only to determine the place value of the first three digit. Only 3, 8, and 7 here are significant figures.