# Surface area of a sphere problem

devildog6289
Sphere 1 has surface area A1 and volume V1, and shere 2 has surface area A2 and volume V2.
If the radius of shere 2 is four times the radius of shere 1, what is the ratio A2/A1 of the areas?

## Answers and Replies

Homework Helper
Surface area of a sphere is 4 Pi R^2 and R2 = 4R1

devildog6289
thank you
and i have 1 more question,
what is the ratio V2/V1 of the volumes?

young e.
devildog6289 said:
thank you
and i have 1 more question,
what is the ratio V2/V1 of the volumes?

V1= 4/3 Π R1^3

V2= 4/3 Π R2^3

Π= PI

DIVIDE BOTH EQUATIONS:

V1= 4/3 Π R1^3
V2= 4/3 Π R2^3

SINCE: R2= 4R1 THEN

V1= 4/3 Π R1^3
V2= 4/3 Π (4R1)^3

V1= 4/3 Π R1^3
V2= 4/3 Π*64*R1^3

CANCEL (4/3, PI & R1^3)

THEREFORE:

V1= 1_
V2= 64

OR V2/V1= 64

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