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

here's a hint \[\huge SA = 4\pi r^2\]
where:
SA = surface area
r = radius

does that help?

Answer 2

I tried it but I keep getting the wrong answers

Answer 3

Are you certain of all those values?

Answer 4

If your surface area is 78.54 sqft, instead of 78.54 sqkm, the answer is in your list.