Question

If the ratio of the radii of two spheres is 1 : 8, what is the ratio of the surface areas of the two spheres?

1 : 64
1 : 8
1 : 512
r2pi : 8r2pi
@michele_laino

Answer 1

surface area is \[4 \pi r ^{2}\]

Answer 2

just focus on the radius in the equation

Answer 3

how does squaring the radius affect both values?

Answer 4

?

Answer 5

\[1^{2} : 8^{2}\]

Answer 6

what does that produce?

Answer 7

what is \[1^{2}\]

Answer 8

1

Answer 9

@10115658

Answer 10

yep, and what's \[8^{2}\]

Answer 11

64

Answer 12

so the answer must be?

Answer 13

well dont you have to have pi in theresomewhere

Answer 14

the pi is a constant term so it just cancels out

Answer 15

so wouldnt it be d or no

Answer 16

really?

Answer 17

yep

Answer 18

If the ratio of the radii of two spheres is 6 : 5, what is the ratio of the surface areas of the two spheres?

36 : 25
6r2pi : 5r2pi
6 : 5
216 : 125
so would this be 36:25

Answer 19

\[4\pi (1)^{2}=4\pi (8)^{2}\]

Answer 20

do you see why the 4pi will cancel?

Answer 21

yes cause both or each sid

Answer 22

that's right

Answer 23

36:25 is also right

Answer 24

Thank You!!!!!

Answer 25

no problem