Question 560114
The surface area of a sphere is directly proportional to the square of its radius r. The volume v of the sphere is directly proportional to the  cube of its radius r. Find the percentage increase in v when s increases by 25%. 
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A 25% increase --> 1.25 times the area
Change in radius = {{{sqrt(1.25)}}}
Change in volume = {{{(sqrt(1.25))^3}}} =~ Vol*1.3975
=~ 39.75% increase in volume