Calculating Volume Change of a Partially Inflated Yoga Ball

[lalahelp]

Homework Statement

Initially, A yoga ball is partially blown up and its surface area measured. Afterwards, it is filled completely and its surface area is found to be 1.50 times as big as it was recorded earlier. By what factor has its volume changed?



Im not sure how to solve for this? can someone explain please

The Attempt at a Solution

 

[Spinnor]

First write down any formulas that you think might help,

Surface area of sphere S = 4*∏*r^2

Volume of a sphere V = [4*∏*r^3]/3

Write down what you know, S2 = 1.5*S1 or

4*∏*r2^2 = 1.5*4*∏*r1^2 simplify and use this to find,

what you want to know, F*V1 = V2 or F = V2/V1 = ? Use the above expression for volume to write out and simplify V2/V1.

Does this get you started?

 

[lalahelp]

No, I don't understand your steps of what to do.