How many non zero digits should numbers written in scientific notation have

All the none-zero digits given should be included when written in scientific notation. But also any trailing zeros written after non-zero digits should also be included.

For example in 0.00900 the 900 is significant because the person who included the trailing zeros is saying look I measured this far and these zeros are significant.

19.side- angle- side

20. angle- side- angle

step-by-step explanation: