Question 86

Consider the following statements.
A. If the radius ofa sphereis increased by 8%, then the Percentage increase in its surface area is 20.86.
B. Ifthe side of'a cubeis increased by 12%, then the percentageincreasein its surface area 1s 25.44.
C. Ifthe radius of acircle is increased by 16%, then the percentage increasein its area is 34.56.
The correct statements among these are

Solution

If the surface area of original sphere is A, then after increasing radius by 8%, new surface area = 1.08*1.08*A = 1.1664*A
16.64% increase in area 

If the surface area of original cube is A, then after increasing side by 12%, new surface area = 1.12*1.12*A = 1.2544*A
25.44% increase in area. 

If the area of original circle is A, then after increasing radius by 16%, new area = 1.16*1.16*A = 1.3456*A
34.56% increase in area. 


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