Question

Find the length of the radius of a sphere with a surface area of 78.54 km2.
A. 5 ft
B. 15 ft
C. 10 ft
D. 2.5 ft

Answer 1

surface area of sphere is given by \(\large S=4\pi r^2\)
here, S =78.54
can you find r ??

Answer 2

how do find R?

Answer 3

i*

Answer 4

by dividing both sides by 4pi, first
and then taking square root.

Answer 5

I don't think i'm doing this right -_- i got like 6.25 and so on

Answer 6

you gor r^2 = 6.25
that is correct!

Answer 7

now simply take square root

Answer 8

i don't have my calculator so i cant do it in my head -_- lmao

Answer 9

ok, \(if, r^2=6.25,r=2.5\)

Answer 10

nvm googled a calculator lol

Answer 11

thank you, i got it now ;b

Answer 12

haha, even i did it with google :P