75. If the radius of a sphere is increased by 50%, find the increase percent in volume and the increase percent in the surface area.
A. 152% B.125%
C.25% D.225%
Answer:
Let original radius = R. Then, new radius = (150/100)R=(3R/2)
Original volume = (4/3)ÕR3, New volume = (4/3)Õ(3R/2)3 =(9ÕR3/2)
Increase % in volume=((19/6)ÕR3)*(3/4ÕR3)*100))% = 237.5%
Original surface area =4ÕR2. New surface area = 4Õ(3R/2)2=9ÕR2
Increase % in surface area =(5ÕR2/4ÕR2) * 100) % = 125%.
