Answer:- There are 5 significant figures in the given measurement.
Explanations:- When there is a decimal in the given number and the zeros are right to a non zero digit then all these ending zeros are significant figures. The given number has two ending zeros and as these are right to the non zero, these are significant figures.
All the middle zeros are always significant figures. All non zeros are always significant figures.
So, the given number has total 5 significant figures in 20.300 m.