Significant Figures (Digits)
Significant digits indicate the precision of a numerical value. A number like 45.67 has 4 significant digits; 45.7 has 3 significant digits.
A result can be no more precise than the information from which it is derived. The precision of a calculation
depends on the precision of the inputs (the loads, dimensions and
other data such as material properties). In most texts, including this one, data is typically assumed to be good to 3 significant digits. In experiments and real-life situatiions, 2 digits may be all that is justifiable.