#2**0 **

20.0185 expressed with 3 significant figures does not always mean to round to 3 figures.

Here is a good reference link http://www.usca.edu/chemistry/genchem/sigfig.htm

All non-zero digits are significant. All zeroes between two significant digits are significant. Zeroes not followed by a significant digit are not significant.

20.0185 has two zeroes and both are significant because they are between the 2 and the 1.

The 2 is significant because it is non-zero. Count the FIRST three significant digits from the left to the right. Do NOT round up or down.

This results in: 20.0

jjzamball
Jun 7, 2014

#3**0 **

http://www.sosmath.com/tables/trigtable/trigtable.html

This link provides the result, however no skill in math is involved.

This would still be a good reference to check your answer.

John

jjzamball
Jun 7, 2014