If the radius of a sphere is increased by 50%, then its surface area will increase by:

125%

50% = \(\frac{1}{2}\)

                                     Original         New

Radius                               2          :      3 

Radius                               2          :      3 

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Surface area (π r²)              4          :      9

Percentage increase in surface area = \(\frac{9 - 4 }{4}\) x 100%

= \(\frac{5}{4}\) x 100%

= 125%