Answer:
Step-by-step explanation:
The surface area of a sphere is given by
A=4πr^2
The volume is
V = (4/3)πr^3
At r = 4":
A = 64π in^2
V = 85.3π in^3
At r = 5" (a 25% increase in r)
A = 100π in^2 (a 156.25% increase)
V = 167π in^3 ( a 195.8% increase)
We can show the ratio of these two measures by dividing the Volume by the Area:
V/A = ((4/3)πr^3/(4πr^2))
V/A = (1/3)r
For the 2 examples (4" and 5"), V/A is:
4": (85.3π in^3)/(64π in^2) = 1.33 [(1/3)r = 4/3 = 1.33]
5": (167π in^3)/(100π in^2) = 1.67 [(1/3)r = 5/3 = 1.67]
V/A = (1/3)r
Since Volume is a function of r^3 and Area is related to r^2, Volume will always increase faster, by a ratio of 1/3 r.
