-All the non-zero numbers are considered significant.
-Zeroes that are in between numbers are significant. e.g. 208
     the zero in between is counted as a significant figure
-leading zeroes are not significant. e.g. 0.0001
     the zeroes before 1 are not counted as significant
-trailing zeroes are significant. e.g. 100
     the zeroes after 1 are significant

For the given number 30.0, there are 3 significant figures/numbers


This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
In 30.0 there are only two significant numbers because if zeroes can be found after the decimal point at the last it is not significant.