Posted by Caitlin on .
A meteorological balloon had a radius of 1.1 m when released at sea level at 20◦C. It ex panded to a radius of 5 m when it had risen to its maximum altitude, where the temperature was −20◦C. What was the pressure inside the balloon at that altitude? The volume of a
sphere is V = 4 π r3 . 3
Answer in units of atm

Chemistry 
DrBob222,
The volume of a sphere is not what you have but (4/3)*pi*r^3.
Calculate volume at both heights and use P1V1 = P2V2