If a spherical ball is enlarged so that its surface area is 9 times greater than its original surface area, then the original radius was multiplied by _________.
Answer

Question

If a spherical ball is enlarged so that its surface area is 9 times greater than its original surface area, then the original radius was multiplied by _________.
Answer

campbell_st · Answer

try  a simple experiment

r = 1   $$SA = 4\pi \times 1^2$$

$$SA = 4 \pi$$

then  9 times the SA

$$36\pi = 4\pi \times r^2$$

$$r^2 = 9$$

the radius is 3

so the length of the radius is tripled

anonymous · Answer

ooh i see so wait that was just an example right?

campbell_st · Answer

no its the solution

but for area the linear ratio is squared

radius 1:3  for area becomes 1^2 : 3^2 or 1: 9

volume is linear ratio cubed

campbell_st · Answer

I gave you a simple way of solving the problem by letting the radius =1 then multiplying the surface area by 9 and then solving for r

anonymous · Answer

oh ok. thank-you