0.072251 contains 5 sigificant figures and 6 decimals. 0.072251 rounded to 4 sig figs is 0.0723, to 3 sig figs is 0.072, and to 2 sig figs is 0.07. To count the number of sig figs in 0.072251, strip the leading insignificant digits (0.0) to get the significant digits (72251).