How many significant figures are in 15.0?

Answer 1

Three in 150.

With trailing zeros it can be ambiguous.

One thing is certain: if you use scientific notation there is nor doubt.

In scientific notation one hundred fifty can be written as

• 1.5 * 102 in which case there are two significant figures

or it can be written as

• 1.50 * 102 (or 15.0*101) with three significant figures

  [However there also is one trailing zerohere!]

or as

• 1.500 * 102 (four significant figures) this also could be expressed as 150.0 - no doubt there that there are four significant figures for zeros to the right of the decimal point!

Answer 2

There are 3 significant figures in 15.0.