The density of a rectangular bar of platinum is 21.4 g/cm3. If the bar is 1.2 cm high, 6.3 cm wide, and has a mass of 1553 grams, how long is the bar?
we know that
The density is equal to divide the mass by the volume
so
D=m/V
In this problem
we have
D=21.4 g/cm3
m=1,553 g
step 1
Find the volume
substitute the given values in the formula
21.4=1,553/V
solve for V
V=1,553/21.4
V=72.57 cm3
step 2
Find out the length of the bar
The volume of the bar is equal to
V=L*W*H
we have
V=72.57 cm3
W=6.3 cm
H=1.2 cm
substitute
72.57=L*6.3*1.2
solve for L
L=72.57/(6.3*1.2)
L=9.6 cm
therefore
the answer is 9.6 cm