As = 4pi*r^2 = Surface area.
100% + 16% = 116% = 1.16
A2/A1 = 4pi*r2^2/4pi*r1^2 = 1.16
The 4pi cancels:
r2^2 / r1^2 = 1.16
Take sq. root of both sides:
r2/r1 = 1.0770 = 107.7%
%Change = 107.7% - 100% = 7.7% Increase.
The surface area is proportional to
the square of the radius:
A spherical baloon expands when it is taken from the cold outdors to the inside of a warm house. if its suface area increases 16%, by what percentage does the radius change
3 answers
7.7%
Therefore, the radius increases by approximately 7.7%.