if the radius of a sphere is tripled, the surface area of a sphere will increase

Question

a) by a factor of 3

 

b) by a factor of 4

 

c)by a factor of 6

 

d)by a factor of 9

Answer 1

d) is the answer because area is always the square of the linear measurement, so if the linear measure (the radius) is tripled (*3) then the surface area would be (*3²) which is nine times (A = 4*PI*R²)