Explanation:
The least number of significant figures in any number of the problem determines the number of significant figures in the answer.
The least precise number present after the decimal point determines the number of significant figures in the answer.
a) 12.3 mm × 15.853 mm :
[tex] 12.3 mm\times 15.853 mm :194.9919 mm^2\approx 195 mm^2[/tex]
Three significant figures.
b) 72.98 · 15.830 ml
[tex]72.98\times 15.830 ml=1,155.2734 ml\approx 1,155 mL[/tex]
Three significant figures.
c) 12.3 mm + 15.853 mm
[tex]12.3 mm + 15.853 mm = 28.153 mm\approx 28.1 mm[/tex]
Three significant figures.
d) 172.3 cm - 15.853 cm
[tex] 172.3 cm - 15.853 cm= 156.447 cm\approx 156.4 cm[/tex]
Four significant figures.