Question

1. [2 pts] Solve for x in the below expressions. How many significant figures are there in the values of x? a) x = 21.00 cm - 20.19 cm b) x = (12.0cm) c) x = (6.9 cm)(2.40 cm) d) x=(16.2 g +1.4 g)/(11.2 cm)

Answer 1

There are three rules on determining how many significant figures are in a number:

1. Non-zero digits are always significant.
2. Any zeros between two significant digits are significant.
3. A final zero or trailing zeros in the decimal portion ONLY are significant.

a)

x= 21.00 cm - 20.19 cm

=0.81 cm

number of significant figure = 2

b)

x= (12.0 cm)^3 = 1728 .000 cm^3

number of significant figure = 7

c)

x = 6.9 cm * 2.40 cm =16.560 cm

number of significant figure = 5

d)

x= (16.2 g+ 1.4g)/(11.2 cm^3)

= 1.571428571 g/cm^3

number of significant figure = 10